*/ESTIMATION PROGRAM FOR PRODUCING ESTIMATES IN 
    "ESTIMATING THE ECONOMIC RETURN TO EDUCATIONAL LEVELS USING DATA ON TWINS"/*;



          */READ IN THE DATA FROM THE SLLS/*;
          */READ IN THE DATA FROM THE SLLS/*;
          */READ IN THE DATA FROM THE SLLS/*;

LIBNAME JOAE 'D:\MINA DOKUMENT 2\AVHANDLING\JAppliedEcon';
 
DATA LNUAE;

  SET JOAE.LNU;

          */PICK OUT SUN1 + SUN2 FROM REGISTER/*;
          */PICK OUT SUN1 + SUN2 FROM REGISTER/*;
          */PICK OUT SUN1 + SUN2 FROM REGISTER/*;


DIRLEVR=K446/1000;
DL1R=INT(DIRLEVR);


          */PICK OUT SUN2 FROM REGISTER/*;
          */PICK OUT SUN2 FROM REGISTER/*;
          */PICK OUT SUN2 FROM REGISTER/*;


DL2R=DL1R/10;
DL3R=INT(DL2R);
LEVR=10*(DL2R-DL3R);



          */CREATE THE EDUCATIONAL LEVEL FROM REGISTER/*;
          */CREATE THE EDUCATIONAL LEVEL FROM REGISTER/*;
          */CREATE THE EDUCATIONAL LEVEL FROM REGISTER/*;


EDLEV=ROUND(LEVR);

IF EDLEV=1 THEN EDU1=1;
ELSE EDU1=0;
IF EDLEV=2 THEN EDU2=1;
ELSE EDU2=0;
IF EDLEV=3 THEN EDU3=1;
ELSE EDU3=0;
IF EDLEV=4 THEN EDU4=1;
ELSE EDU4=0;
IF EDLEV=5 THEN EDU5=1;
ELSE EDU5=0;
IF EDLEV=6 THEN EDU6=1;
ELSE EDU6=0;
IF EDLEV=7 THEN EDU7=1;
ELSE EDU7=0;

    */CREATE A VARIABLE THAT IS EQUAL TO 1 IF THE INDIVIDUAL HAS ONE OF EDUCATIONAL LEVELS 1 - 7/*;
    */CREATE A VARIABLE THAT IS EQUAL TO 1 IF THE INDIVIDUAL HAS ONE OF EDUCATIONAL LEVELS 1 - 7/*;
    */CREATE A VARIABLE THAT IS EQUAL TO 1 IF THE INDIVIDUAL HAS ONE OF EDUCATIONAL LEVELS 1 - 7/*;

ESUM=EDU1+EDU2+EDU3+EDU4+EDU5+EDU6+EDU7;

          */YEARS OF SCHOOLING, S/*;
          */YEARS OF SCHOOLING, S/*;
          */YEARS OF SCHOOLING, S/*;

S=y131;

          */SEX=0 IF FEMALE AND SEX=1 IF MALE/*;
          */SEX=0 IF FEMALE AND SEX=1 IF MALE/*;
          */SEX=0 IF FEMALE AND SEX=1 IF MALE/*;


IF Y10=2 THEN SEX=0;
IF Y10=1 THEN SEX=1;


          */BIRTHYEAR/*;
          */BIRTHYEAR/*;
          */BIRTHYEAR/*;


BYEAR=Y11;

          */AGE VARIABLES IN 1987, 1990 AND 1993/*;
          */AGE VARIABLES IN 1987, 1990 AND 1993/*;
          */AGE VARIABLES IN 1987, 1990 AND 1993/*;

AGE87=87-Y11;
AGE90=90-Y11;
AGE93=93-Y11;
AGE91=91-Y11;

AGE=(AGE87+AGE90+AGE93)/3;

AGE87Q=AGE87**2;
AGE90Q=AGE90**2;
AGE93Q=AGE93**2;
AGEQ=(AGE87Q+AGE90Q+AGE93Q)/3;

          */A DUMMY VARIABLE INDICATING WHERE THE INDIVIDUAL IS BORN/*;
          */A DUMMY VARIABLE INDICATING WHERE THE INDIVIDUAL IS BORN/*;
          */A DUMMY VARIABLE INDICATING WHERE THE INDIVIDUAL IS BORN/*;

IF Y19=. OR Y19=0 OR Y19=10 THEN SWE=1;
ELSE SWE=0;

PROC PRINT;
QUIT;
RUN;

          */THE FOLLOWING DATA STEP IS USED TO CHECK THE CREATION OF THE EDUCATIONAL LEVELS/*;
          */THE FOLLOWING DATA STEP IS USED TO CHECK THE CREATION OF THE EDUCATIONAL LEVELS/*;
          */THE FOLLOWING DATA STEP IS USED TO CHECK THE CREATION OF THE EDUCATIONAL LEVELS/*;

DATA CHECK;

        SET LNUAE;


          */EDLEV PICKS OUT POSITION 2 FROM K446/*;
          */EDLEV PICKS OUT POSITION 2 FROM K446/*;
          */EDLEV PICKS OUT POSITION 2 FROM K446/*;


PROC PRINT;VAR K446 EDLEV;

QUIT;
RUN;

          */THE FOLLOWING DATA STEPS CREATES A MODEL TO EXPLAIN THE YEARS OF SCHOOL, S,
                        BY MEANS OF EDUCATION LEVEL, SUN2/*;

          */THE FOLLOWING DATA STEPS CREATES A MODEL TO EXPLAIN THE YEARS OF SCHOOL, S,
                        BY MEANS OF EDUCATION LEVEL, SUN2/*;

          */THE FOLLOWING DATA STEPS CREATES A MODEL TO EXPLAIN THE YEARS OF SCHOOL, S,
                        BY MEANS OF EDUCATION LEVEL, SUN2/*;


DATA LNUAF;

        SET LNUAE;

IF AGE90 GE 32 AND AGE93 LT 65;
IF SWE=1;
IF S NE .;
IF S NE 99;
IF ESUM=1;

IF I246 GT 0;
IF K50 GT 0;
IF K727 GT 0;

      */DEFINE EARNINGS IN 1987, 1990 AND 1993 IN REAL TERMS (1990:S PRICES)/*;
      */DEFINE EARNINGS IN 1987, 1990 AND 1993 IN REAL TERMS (1990:S PRICES)/*;
      */DEFINE EARNINGS IN 1987, 1990 AND 1993 IN REAL TERMS (1990:S PRICES)/*;

INC87=I246/0.8044;
INC90=K50/100;              */DIVIDE BY 100 TO MAKE COMPARABLE TO I246/*;
INC93=(K727/100)/1.1715;    */DIVIDE BY 100 TO MAKE COMPARABLE TO I246/*;

INC=(INC87+INC90+INC93)/3;

LINC87=LOG(INC87);
LINC90=LOG(INC90);
LINC93=LOG(INC93);

LINC=(LINC87+LINC90+LINC93)/3;

   */IN THE FOLLOWING DATA STEP I CHECK THE DIFFERENCES BETWEEN USING PREDICTED
                AND SELFREPORTED SCHOOLING USING THE LNU DATA SET/*;

   */IN THE FOLLOWING DATA STEP I CHECK THE DIFFERENCES BETWEEN USING PREDICTED
                AND SELFREPORTED SCHOOLING USING THE LNU DATA SET/*;

   */IN THE FOLLOWING DATA STEP I CHECK THE DIFFERENCES BETWEEN USING PREDICTED
                AND SELFREPORTED SCHOOLING USING THE LNU DATA SET/*;

DATA SPECB;

        SET LNUAF;

IF INC87 GT 600;
IF INC90 GT 600;
IF INC93 GT 600;

IF EDU2=1 OR EDU3=1 OR EDU4=1 OR EDU5=1 OR EDU6=1 OR EDU7=1 THEN SD21=9.7461929-7.6931217;
ELSE SD21=0;

IF EDU3=1 OR EDU4=1 OR EDU5=1 OR EDU6=1 OR EDU7=1 THEN SD32=10.397476-9.7461929;
ELSE SD32=0;

IF EDU4=1 OR EDU5=1 OR EDU6=1 OR EDU7=1 THEN SD43=12.364444-10.397476;
ELSE SD43=0;

IF EDU5=1 OR EDU6=1 OR EDU7=1 THEN SD54=13.372093-12.364444;
ELSE SD54=0;

IF EDU6=1 OR EDU7=1 THEN SD65=16.532-13.372093;
ELSE SD65=0;

IF EDU7=1 THEN SD76=19.272727-16.532;
ELSE SD76=0;

            */THE AVERAGE EARNINGS IN 1987, 1990 AND 1993/*;
            */THE AVERAGE EARNINGS IN 1987, 1990 AND 1993/*;
            */THE AVERAGE EARNINGS IN 1987, 1990 AND 1993/*;

INC=(INC87+INC90+INC93)/3;

PROC MEANS;VAR INC S EDU1 EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 AGE SEX;

PROC REG;

        MODEL S=EDU1 EDU2 EDU3 EDU4 EDU5 EDU6 EDU7/NOINT;
        MODEL S=EDU2 EDU3 EDU4 EDU5 EDU6 EDU7;
        MODEL LINC=EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 AGE AGEQ SEX;
        MODEL LINC=S AGE AGEQ SEX;

QUIT;
RUN;

PROC REG;

        MODEL LINC=SD21 SD32 SD43 SD54 SD65 SD76 AGE AGEQ SEX;
        LINJE1:TEST SD21=SD32=SD43=SD54=SD65=SD76;

QUIT;
RUN;

*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;
*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;
*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;



          */THE FOLLOWING TWO DATA STEPS READ THE DATA AND TRANSFORM CHARACTER
                                VALUES TO NUMERIC VALUES*/;

          */THE FOLLOWING TWO DATA STEPS READ THE DATA AND TRANSFORM CHARACTER
                                VALUES TO NUMERIC VALUES*/;

          */THE FOLLOWING TWO DATA STEPS READ THE DATA AND TRANSFORM CHARACTER
                                VALUES TO NUMERIC VALUES*/;

DATA A;

  SET JOAE.TWINS;

          */DEPENDING ON WHICH ZYGO TO CONDUCT THE ANALYSIS CHANGE HERE!/;
          */DEPENDING ON WHICH ZYGO TO CONDUCT THE ANALYSIS CHANGE HERE!/;
          */DEPENDING ON WHICH ZYGO TO CONDUCT THE ANALYSIS CHANGE HERE!/;

  */ZYGO=1 IMPLIES MZ TWINS, ZYGO=2 IMPLIES DZ TWINS AND ZYGO=3 IMPLIES INDETERMINATE CASES/*;
  */ZYGO=1 IMPLIES MZ TWINS, ZYGO=2 IMPLIES DZ TWINS AND ZYGO=3 IMPLIES INDETERMINATE CASES/*;
  */ZYGO=1 IMPLIES MZ TWINS, ZYGO=2 IMPLIES DZ TWINS AND ZYGO=3 IMPLIES INDETERMINATE CASES/*;

IF ZYG=2;

LENGTH BORN 8;

LENGTH EDLEV 8;

LENGTH AINK87I 8;
LENGTH AINK90I 8;
LENGTH AINK93I 8;

LENGTH TWNR 8;
LENGTH PAIR 8;
LENGTH SEP 8;

LENGTH CI88 8;
LENGTH CI90 8;
LENGTH CI93 8;

                            */BIRTH YEAR/*;
                            */BIRTH YEAR/*;
                            */BIRTH YEAR/*;

BORN=BYEAR;

                    */A DUMMY VARIABLE FOR SEX/*;
                    */A DUMMY VARIABLE FOR SEX/*;
                    */A DUMMY VARIABLE FOR SEX/*;

IF SEX=1 THEN SEXE=1;
IF SEX=2 THEN SEXE=0;

                    */EDLEV=THE EDUCATION LEVEL (SUN2)/*;
                    */EDLEV=THE EDUCATION LEVEL (SUN2)/*;
                    */EDLEV=THE EDUCATION LEVEL (SUN2)/*;

EDLEV=SCB64;

*/DEFINE NOMINAL EARNINGS IN 1987, 1990 AND 1993 RESPECTIVELY/*;

*/DEFINE NOMINAL EARNINGS IN 1987, 1990 AND 1993 RESPECTIVELY/*;

*/DEFINE NOMINAL EARNINGS IN 1987, 1990 AND 1993 RESPECTIVELY/*;

AINK87I=SCB14;
AINK90I=SCB31;
AINK93I=SCB48;

      */IDENTIFICATIONS FOR TWNR=1 OR 2 AND PAIR=1, 2, ... TOTAL NO OF PAIRS/*;
      */IDENTIFICATIONS FOR TWNR=1 OR 2 AND PAIR=1, 2, ... TOTAL NO OF PAIRS/*;
      */IDENTIFICATIONS FOR TWNR=1 OR 2 AND PAIR=1, 2, ... TOTAL NO OF PAIRS/*;

TWNR=TVAB;
PAIR=PARNR;

          */AGE OF SEPARATION/*;
          */AGE OF SEPARATION/*;
          */AGE OF SEPARATION/*;


SEP=NYRA62;


          */AGE IN 1987/*;
          */AGE IN 1987/*;
          */AGE IN 1987/*;

AGE87=87-BORN;

          */AGE-SQUARED IN 1987/*;
          */AGE-SQUARED IN 1987/*;
          */AGE-SQUARED IN 1987/*;


AGE87Q=AGE87**2;

          */AGE IN 1990/*;
          */AGE IN 1990/*;
          */AGE IN 1990/*;


AGE90=90-BORN;


          */AGE-SQUARED IN 1990/*;
          */AGE-SQUARED IN 1990/*;
          */AGE-SQUARED IN 1990/*;


AGE90Q=AGE90**2;


          */AGE IN 1993/*;
          */AGE IN 1993/*;
          */AGE IN 1993/*;


AGE93=93-BORN;


          */AGE-SQUARED IN 1993/*;
          */AGE-SQUARED IN 1993/*;
          */AGE-SQUARED IN 1993/*;


AGE93Q=AGE93**2;

          */HERE COMES THE DUMMYVARIABLES FOR EDUCATIONAL LEVEL/*;
          */HERE COMES THE DUMMYVARIABLES FOR EDUCATIONAL LEVEL/*;
          */HERE COMES THE DUMMYVARIABLES FOR EDUCATIONAL LEVEL/*;

IF EDLEV=1 THEN EDU1=1;
ELSE EDU1=0;
IF EDLEV=2 THEN EDU2=1;
ELSE EDU2=0;
IF EDLEV=3 THEN EDU3=1;
ELSE EDU3=0;
IF EDLEV=4 THEN EDU4=1;
ELSE EDU4=0;
IF EDLEV=5 THEN EDU5=1;
ELSE EDU5=0;
IF EDLEV=6 THEN EDU6=1;
ELSE EDU6=0;
IF EDLEV=7 THEN EDU7=1;
ELSE EDU7=0;

ESUM=EDU1+EDU2+EDU3+EDU4+EDU5+EDU6+EDU7;

DATA DEFLATE;

        SET A;

          */REMOVE THE MISSING VALUES ON EDUCATIONAL LEVEL/*;
          */REMOVE THE MISSING VALUES ON EDUCATIONAL LEVEL/*;
          */REMOVE THE MISSING VALUES ON EDUCATIONAL LEVEL/*;

IF ESUM=1;

          */REMOVE MISSING VALUES ON ANNUAL EARNINGS IN THE THREE YEARS/*;
          */REMOVE MISSING VALUES ON ANNUAL EARNINGS IN THE THREE YEARS/*;
          */REMOVE MISSING VALUES ON ANNUAL EARNINGS IN THE THREE YEARS/*;

IF AINK87I NE .;
IF AINK90I NE .;
IF AINK93I NE .;

          */DEFLATE REAL ANNUAL EARNINGS IN 1987 AND 1993, 1990:S PRICES/*;
          */DEFLATE REAL ANNUAL EARNINGS IN 1987 AND 1993, 1990:S PRICES/*;
          */DEFLATE REAL ANNUAL EARNINGS IN 1987 AND 1993, 1990:S PRICES/*;


AINK87=AINK87I/0.8044;
AINK90=AINK90I;
AINK93=AINK93I/1.1715;

          */A SIMPLE IMPUTATION OF YEARS OF SCHOOLING/*;

IF EDU1=1 THEN S=7.69312;
IF EDU2=1 THEN S=9.74619;
IF EDU3=1 THEN S=10.39748;
IF EDU4=1 THEN S=12.36444;
IF EDU5=1 THEN S=13.37209;
IF EDU6=1 THEN S= 16.53200;
IF EDU7=1 THEN S=19.27273;

        */THE FOLLOWING DATA STEP REDEFINES AND CREATES A FEW NEW VARIABLES
        AND SETS THE LOWEST LEVEL OF INCOME ON THOSE INDIVIDUALS/PAIRS TO
                                INCLUDE IN THE ANALYSIS/*;

        */THE FOLLOWING DATA STEP REDEFINES AND CREATES A FEW NEW VARIABLES
        AND SETS THE LOWEST LEVEL OF INCOME ON THOSE INDIVIDUALS/PAIRS TO
                                INCLUDE IN THE ANALYSIS/*;

        */THE FOLLOWING DATA STEP REDEFINES AND CREATES A FEW NEW VARIABLES
        AND SETS THE LOWEST LEVEL OF INCOME ON THOSE INDIVIDUALS/PAIRS TO
                                INCLUDE IN THE ANALYSIS/*;

DATA C;
        SET DEFLATE (KEEP=PAIR TWNR BORN
        EDLEV EDU1 EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 S
        AINK87 AINK90 AINK93
        AGE87 AGE87Q AGE90 AGE90Q AGE93 AGE93Q ZYG SEXE
        SEP);

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1987
                            OF THE INDIVIDUALS IN THE SAMPLE/*;

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1987
                            OF THE INDIVIDUALS IN THE SAMPLE/*;

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1987
                            OF THE INDIVIDUALS IN THE SAMPLE/*;

IF AINK87 GT 600;
IF AINK87 NE .;

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1990
                            OF THE INDIVIDUALS IN THE SAMPLE/*;

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1990
                            OF THE INDIVIDUALS IN THE SAMPLE/*;

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1990
                            OF THE INDIVIDUALS IN THE SAMPLE/*;


IF AINK90 GT 600;
IF AINK90 NE .;

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1993
                           OF THE INDIVIDUALS IN THE SAMPLE/*;

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1993
                           OF THE INDIVIDUALS IN THE SAMPLE/*;

            */DEFINE LOWEST LEVEL OF EARNINGS IN 1993
                           OF THE INDIVIDUALS IN THE SAMPLE/*;

IF AINK93 GT 600;
IF AINK93 NE .;

                     */AGE-RESTRICTION/*;
                     */AGE-RESTRICTION/*;
                     */AGE-RESTRICTION/*;

IF AGE93 LT 65;

 */CREATE THE NATURAL LOGARITHMS OF EARNINGS IN EACH RESP. YEAR/*;
 */CREATE THE NATURAL LOGARITHMS OF EARNINGS IN EACH RESP. YEAR/*;
 */CREATE THE NATURAL LOGARITHMS OF EARNINGS IN EACH RESP. YEAR/*;

LAINK87=LOG(AINK87);
LAINK90=LOG(AINK90);
LAINK93=LOG(AINK93);

                    */THE AVERAGE LOG OF EARNINGS/*;
                    */THE AVERAGE LOG OF EARNINGS/*;
                    */THE AVERAGE LOG OF EARNINGS/*;

LAINK=(LAINK87+LAINK90+LAINK93)/3;

                            */THE AVERAGE AGE/*;
                            */THE AVERAGE AGE/*;
                            */THE AVERAGE AGE/*;

AGE=(AGE87+AGE90+AGE93)/3;

                            */THE AVERAGE AGEQ/*;
                            */THE AVERAGE AGEQ/*;
                            */THE AVERAGE AGEQ/*;

AGEQ=(AGE87Q+AGE90Q+AGE93Q)/3;

*/THE FOLLOWING DATA STEP STARTS TO DIVIDE THE SAMPLE INTO TWO PARTS
                                   -TWIN NO.1 AND NO.2/*;

*/THE FOLLOWING DATA STEP STARTS TO DIVIDE THE SAMPLE INTO TWO PARTS
                                   -TWIN NO.1 AND NO.2/*;

*/THE FOLLOWING DATA STEP STARTS TO DIVIDE THE SAMPLE INTO TWO PARTS
                                   -TWIN NO.1 AND NO.2/*;

DATA D;
        SET C;

IF TWNR=1;

            */ADD AN INDEX=1 FOR EACH VARIABLE/*;
            */ADD AN INDEX=1 FOR EACH VARIABLE/*;
            */ADD AN INDEX=1 FOR EACH VARIABLE/*;

TWNR1=TWNR;

EDLEV1=EDLEV;
EDU11=EDU1;
EDU21=EDU2;
EDU31=EDU3;
EDU41=EDU4;
EDU51=EDU5;
EDU61=EDU6;
EDU71=EDU7;

S1=S;

AINK871=AINK87;
LAINK871=LAINK87;

AINK901=AINK90;
LAINK901=LAINK90;

AINK931=AINK93;
LAINK931=LAINK93;

LAINK1=LAINK;

AGE871=AGE87;
AGE87Q1=AGE87Q;

AGE901=AGE90;
AGE90Q1=AGE90Q;

AGE931=AGE93;
AGE93Q1=AGE93Q;

AGE1=AGE;
AGEQ1=AGEQ;

ZYG1=ZYG;

SEXE1=SEXE;

SEP1=SEP;

DROP TWNR BORN EDLEV EDU1 EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 S
AINK87 LAINK87 AINK90 LAINK90 AINK93 LAINK93 LAINK
AGE87 AGE87Q AGE90 AGE90Q AGE93 AGE93Q AGE AGEQ ZYG SEXE
SEP;

DATA E;
        SET C;

IF TWNR=2;

            */ADD AN INDEX=2 FOR EACH VARIABLE/*;
            */ADD AN INDEX=2 FOR EACH VARIABLE/*;
            */ADD AN INDEX=2 FOR EACH VARIABLE/*;

TWNR2=TWNR;

EDLEV2=EDLEV;
EDU12=EDU1;
EDU22=EDU2;
EDU32=EDU3;
EDU42=EDU4;
EDU52=EDU5;
EDU62=EDU6;
EDU72=EDU7;

S2=S;

AINK872=AINK87;
LAINK872=LAINK87;

AINK902=AINK90;
LAINK902=LAINK90;

AINK932=AINK93;
LAINK932=LAINK93;

LAINK2=LAINK;

AGE872=AGE87;
AGE87Q2=AGE87Q;

AGE902=AGE90;
AGE90Q2=AGE90Q;

AGE932=AGE93;
AGE93Q2=AGE93Q;

AGE2=AGE;
AGEQ2=AGEQ;

ZYG2=ZYG;

SEXE2=SEXE;

SEP2=SEP;

DROP TWNR BORN EDLEV EDU1 EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 S
AINK87 LAINK87 AINK90 LAINK90 AINK93 LAINK93 LAINK
AGE87 AGE87Q AGE90 AGE90Q AGE93 AGE93Q AGE AGEQ ZYG SEXE
SEP;

      */THE FOLLOWING DATA STEP DEFINE THE VARIABLES NEEDED FOR THE FIXED EFFECTS ANALYSIS/*;
      */THE FOLLOWING DATA STEP DEFINE THE VARIABLES NEEDED FOR THE FIXED EFFECTS ANALYSIS/*;
      */THE FOLLOWING DATA STEP DEFINE THE VARIABLES NEEDED FOR THE FIXED EFFECTS ANALYSIS/*;

DATA F;
        MERGE D E;BY PAIR;

IF LAINK871 NE .;
IF LAINK901 NE .;
IF LAINK931 NE .;
IF LAINK872 NE .;
IF LAINK902 NE .;
IF LAINK932 NE .;

    */THE WITHIN-PAIR DIFFERENCE IN EDUCATIONAL LEVELS/*;
    */THE WITHIN-PAIR DIFFERENCE IN EDUCATIONAL LEVELS/*;
    */THE WITHIN-PAIR DIFFERENCE IN EDUCATIONAL LEVELS/*;

DEDU1=EDU11-EDU12;
DEDU2=EDU21-EDU22;
DEDU3=EDU31-EDU32;
DEDU4=EDU41-EDU42;
DEDU5=EDU51-EDU52;
DEDU6=EDU61-EDU62;
DEDU7=EDU71-EDU72;

DS=S1-S2;
    */THE WITHIN-PAIR DIFFERENCE IN LOG-EARNINGS/*;
    */THE WITHIN-PAIR DIFFERENCE IN LOG-EARNINGS/*;
    */THE WITHIN-PAIR DIFFERENCE IN LOG-EARNINGS/*;

DLAINK87=LAINK871-LAINK872;

DLAINK90=LAINK901-LAINK902;

DLAINK93=LAINK931-LAINK932;

DLAINK=LAINK1-LAINK2;

    */IMPUTE LOWEST STATED AGE OF SEPARATION WHENEVER THE TWO REPORTS DIFFER/*;
    */IMPUTE LOWEST STATED AGE OF SEPARATION WHENEVER THE TWO REPORTS DIFFER/*;
    */IMPUTE LOWEST STATED AGE OF SEPARATION WHENEVER THE TWO REPORTS DIFFER/*;


IF SEP1=. THEN SEP1=SEP2;
IF SEP2=. THEN SEP2=SEP1;

IF SEP1 LE SEP2 THEN SEPARATE=SEP1;
ELSE SEPARATE=SEP2;

DATA GBASE2;
        SET F;

IF SEPARATE=. OR SEPARATE GE 15;

IF DLAINK87 NE .;
IF DLAINK90 NE .;
IF DLAINK93 NE .;

IF DEDU1 NE .;
IF DEDU2 NE .;
IF DEDU3 NE .;
IF DEDU4 NE .;
IF DEDU5 NE .;
IF DEDU6 NE .;
IF DEDU7 NE .;

IF EDU21=1 OR EDU31=1 OR EDU41=1 OR EDU51=1 OR EDU61=1 OR EDU71=1 THEN SD211=9.7461929-7.6931217;
ELSE SD211=0;

IF EDU31=1 OR EDU41=1 OR EDU51=1 OR EDU61=1 OR EDU71=1 THEN SD321=10.397476-9.7461929;
ELSE SD321=0;

IF EDU41=1 OR EDU51=1 OR EDU61=1 OR EDU71=1 THEN SD431=12.364444-10.397476;
ELSE SD431=0;

IF EDU51=1 OR EDU61=1 OR EDU71=1 THEN SD541=13.372093-12.364444;
ELSE SD541=0;

IF EDU61=1 OR EDU71=1 THEN SD651=16.532-13.372093;
ELSE SD651=0;

IF EDU71=1 THEN SD761=19.272727-16.532;
ELSE SD761=0;


IF EDU22=1 OR EDU32=1 OR EDU42=1 OR EDU52=1 OR EDU62=1 OR EDU72=1 THEN SD212=9.7461929-7.6931217;
ELSE SD212=0;

IF EDU32=1 OR EDU42=1 OR EDU52=1 OR EDU62=1 OR EDU72=1 THEN SD322=10.397476-9.7461929;
ELSE SD322=0;

IF EDU42=1 OR EDU52=1 OR EDU62=1 OR EDU72=1 THEN SD432=12.364444-10.397476;
ELSE SD432=0;

IF EDU52=1 OR EDU62=1 OR EDU72=1 THEN SD542=13.372093-12.364444;
ELSE SD542=0;

IF EDU62=1 OR EDU72=1 THEN SD652=16.532-13.372093;
ELSE SD652=0;

IF EDU72=1 THEN SD762=19.272727-16.532;
ELSE SD762=0;

DSD21=SD211-SD212;
DSD32=SD321-SD322;
DSD43=SD431-SD432;
DSD54=SD541-SD542;
DSD65=SD651-SD652;
DSD76=SD761-SD762;

PROC FREQ;TABLES EDLEV1*EDLEV2;

PROC CORR;VAR LAINK871 LAINK872 LAINK901 LAINK902 LAINK931 LAINK932 S1 S2;

PROC REG;

        MODEL DLAINK87=DEDU2 DEDU3 DEDU4 DEDU5 DEDU6 DEDU7/NOINT;
        MODEL DLAINK90=DEDU2 DEDU3 DEDU4 DEDU5 DEDU6 DEDU7/NOINT;
        MODEL DLAINK93=DEDU2 DEDU3 DEDU4 DEDU5 DEDU6 DEDU7/NOINT;
        MODEL DLAINK=DEDU2 DEDU3 DEDU4 DEDU5 DEDU6 DEDU7/NOINT;
        MODEL DLAINK=DS/NOINT;

QUIT;
RUN;

PROC REG;

        MODEL DLAINK=DSD21 DSD32 DSD43 DSD54 DSD65 DSD76/NOINT;

QUIT;
RUN;

        */THIS COMPLETES THE FE ANALYSIS FOR EDUCATION LEVELS/*;
        */THIS COMPLETES THE FE ANALYSIS FOR EDUCATION LEVELS/*;
        */THIS COMPLETES THE FE ANALYSIS FOR EDUCATION LEVELS/*;

        */START OF THE OLS AND GLS ANALYSIS ON EDUCATION LEVELS/*;
        */START OF THE OLS AND GLS ANALYSIS ON EDUCATION LEVELS/*;
        */START OF THE OLS AND GLS ANALYSIS ON EDUCATION LEVELS/*;

DATA H;
        SET GBASE2 (KEEP=PAIR TWNR1 EDU11 EDU21 EDU31 EDU41 EDU51 EDU61 EDU71 S1
        AINK871 LAINK871 AINK901 LAINK901 AINK931 LAINK931 LAINK1
        AGE871 AGE87Q1 AGE901 AGE90Q1 AGE931 AGE93Q1 AGE1 AGEQ1 SEXE1 ZYG1);

TWNR=TWNR1;

EDU1=EDU11;
EDU2=EDU21;
EDU3=EDU31;
EDU4=EDU41;
EDU5=EDU51;
EDU6=EDU61;
EDU7=EDU71;

S=S1;

AINK87=AINK871;
LAINK87=LAINK871;

AINK90=AINK901;
LAINK90=LAINK901;

AINK93=AINK931;
LAINK93=LAINK931;

LAINK=LAINK1;

AGE87=AGE871;
AGE87Q=AGE87Q1;

AGE90=AGE901;
AGE90Q=AGE90Q1;

AGE93=AGE931;
AGE93Q=AGE93Q1;

AGE=AGE1;
AGEQ=AGEQ1;

SEXE=SEXE1;

ZYG=ZYG1;

DROP TWNR1 EDU11 EDU21 EDU31 EDU41 EDU51 EDU61 EDU71 S1
AINK871 LAINK871 AINK901 LAINK901 AINK931 LAINK931 LAINK1
AGE871 AGE87Q1 AGE901 AGE90Q1 AGE931 AGE93Q1 AGE1 AGEQ1 SEXE1 ZYG1;

DATA I;
        SET GBASE2 (KEEP=PAIR TWNR2 EDU12 EDU22 EDU32 EDU42 EDU52 EDU62 EDU72 S2
        AINK872 LAINK872 AINK902 LAINK902 AINK932 LAINK932 LAINK2
        AGE872 AGE87Q2 AGE902 AGE90Q2 AGE932 AGE93Q2 AGE2 AGEQ2 SEXE2 ZYG2);

TWNR=TWNR2;

EDU1=EDU12;
EDU2=EDU22;
EDU3=EDU32;
EDU4=EDU42;
EDU5=EDU52;
EDU6=EDU62;
EDU7=EDU72;

S=S2;

AINK87=AINK872;
LAINK87=LAINK872;

AINK90=AINK902;
LAINK90=LAINK902;

AINK93=AINK932;
LAINK93=LAINK932;

LAINK=LAINK2;

AGE87=AGE872;
AGE87Q=AGE87Q2;

AGE90=AGE902;
AGE90Q=AGE90Q2;

AGE93=AGE932;
AGE93Q=AGE93Q2;

AGE=AGE2;
AGEQ=AGEQ2;

SEXE=SEXE2;

ZYG=ZYG2;

DROP TWNR2 EDU12 EDU22 EDU32 EDU42 EDU52 EDU62 EDU72 S2
AINK872 LAINK872 AINK902 LAINK902 AINK932 LAINK932 LAINK2
AGE872 AGE87Q2 AGE902 AGE90Q2 AGE932 AGE93Q2 AGE2 AGEQ2 SEXE2 ZYG2;

            */NOW PUT THE TWO DATASETS TOGETHER AGAIN/*;
            */NOW PUT THE TWO DATASETS TOGETHER AGAIN/*;
            */NOW PUT THE TWO DATASETS TOGETHER AGAIN/*;

        */MAKE THE REGRESSIONS FOR THE BASIC SPECIFICATION IN THE OLS MODEL/*;
        */MAKE THE REGRESSIONS FOR THE BASIC SPECIFICATION IN THE OLS MODEL/*;
        */MAKE THE REGRESSIONS FOR THE BASIC SPECIFICATION IN THE OLS MODEL/*;

DATA J;
        SET H I;

IF EDU2=1 OR EDU3=1 OR EDU4=1 OR EDU5=1 OR EDU6=1 OR EDU7=1 THEN SD21=9.7461929-7.6931217;
ELSE SD21=0;

IF EDU3=1 OR EDU4=1 OR EDU5=1 OR EDU6=1 OR EDU7=1 THEN SD32=10.397476-9.7461929;
ELSE SD32=0;

IF EDU4=1 OR EDU5=1 OR EDU6=1 OR EDU7=1 THEN SD43=12.364444-10.397476;
ELSE SD43=0;

IF EDU5=1 OR EDU6=1 OR EDU7=1 THEN SD54=13.372093-12.364444;
ELSE SD54=0;

IF EDU6=1 OR EDU7=1 THEN SD65=16.532-13.372093;
ELSE SD65=0;

IF EDU7=1 THEN SD76=19.272727-16.532;
ELSE SD76=0;

AINK=(AINK87+AINK90+AINK93)/3;

PROC MEANS;VAR AINK EDU1 EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 SEXE AGE;

PROC REG;

        MODEL LAINK87=EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 AGE87 AGE87Q SEXE;
        MODEL LAINK90=EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 AGE90 AGE90Q SEXE;
        MODEL LAINK93=EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 AGE93 AGE93Q SEXE;
        MODEL LAINK=EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 AGE93 AGE93Q SEXE;

        MODEL LAINK=EDU1 EDU2 EDU3 EDU4 EDU5 EDU6 EDU7 AGE AGEQ SEXE/NOINT;
        MODEL LAINK=S AGE AGEQ SEXE;

QUIT;
RUN;

PROC REG;

        MODEL LAINK=SD21 SD32 SD43 SD54 SD65 SD76 AGE AGEQ SEXE;
        LINJE1:TEST SD21=SD32=SD43=SD54=SD65=SD76;

QUIT;
RUN;

*/THE FOLLOWING PART OF THE PROGRAM IS USED TO PRODUCE ESTIMATES OF S THAT ARE NOT INCONS.
BECAUSE OF CLASSIFICATION ERROR IN EDUCATIONAL LEVEL/*;

*/THE FOLLOWING PART OF THE PROGRAM IS USED TO PRODUCE ESTIMATES OF S THAT ARE NOT INCONS.
BECAUSE OF CLASSIFICATION ERROR IN EDUCATIONAL LEVEL/*;

*/THE FOLLOWING PART OF THE PROGRAM IS USED TO PRODUCE ESTIMATES OF S THAT ARE NOT INCONS.
BECAUSE OF CLASSIFICATION ERROR IN EDUCATIONAL LEVEL/*;

*/LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU/*;
*/LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU/*;
*/LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU LNU/*;

PROC IML;

USE SPECB VAR{LINC};READ ALL INTO LINC;
USE SPECB VAR{S};READ ALL INTO S;
USE SPECB VAR{AGE};READ ALL INTO AGE;
USE SPECB VAR{AGEQ};READ ALL INTO AGEQ;
USE SPECB VAR{SEX};READ ALL INTO SEXE;
USE SPECB VAR{EDU1};READ ALL INTO EDU1;
USE SPECB VAR{EDU2};READ ALL INTO EDU2;
USE SPECB VAR{EDU3};READ ALL INTO EDU3;
USE SPECB VAR{EDU4};READ ALL INTO EDU4;
USE SPECB VAR{EDU5};READ ALL INTO EDU5;
USE SPECB VAR{EDU6};READ ALL INTO EDU6;
USE SPECB VAR{EDU7};READ ALL INTO EDU7;


            */FIRST ESTIMATE THE IMPUTATION MODEL ON THE SLLS/*;
            */FIRST ESTIMATE THE IMPUTATION MODEL ON THE SLLS/*;
            */FIRST ESTIMATE THE IMPUTATION MODEL ON THE SLLS/*;

NSLLS=NROW(LINC);
PRINT NSLLS;

XOBS=EDU1||EDU2||EDU3||EDU4||EDU5||EDU6||EDU7;

KSLLS=NCOL(XOBS);

NSLLS1=SUM(EDU1);
NSLLS2=SUM(EDU2);
NSLLS3=SUM(EDU3);
NSLLS4=SUM(EDU4);
NSLLS5=SUM(EDU5);
NSLLS6=SUM(EDU6);
NSLLS7=SUM(EDU7);

PRINT NSLLS1;
PRINT NSLLS2;
PRINT NSLLS3;
PRINT NSLLS4;
PRINT NSLLS5;
PRINT NSLLS6;
PRINT NSLLS7;

*/CORRECTION MATRICES/*;

DBAR1=SUM(EDU1)/NSLLS;
DBAR2=SUM(EDU2)/NSLLS;
DBAR3=SUM(EDU3)/NSLLS;
DBAR4=SUM(EDU4)/NSLLS;
DBAR5=SUM(EDU5)/NSLLS;
DBAR6=SUM(EDU6)/NSLLS;
DBAR7=SUM(EDU7)/NSLLS;

ABAR=DBAR1||DBAR2||DBAR3||DBAR4||DBAR5||DBAR6||DBAR7;
PRINT ABAR;

  */A CONTROL THAT THE AVERAGES FOR EDUCATIONAL LEVEL SUM TO ONE/*;
  */A CONTROL THAT THE AVERAGES FOR EDUCATIONAL LEVEL SUM TO ONE/*;
  */A CONTROL THAT THE AVERAGES FOR EDUCATIONAL LEVEL SUM TO ONE/*;

SDBAR=DBAR1+DBAR2+DBAR3+DBAR4+DBAR5+DBAR6+DBAR7;
PRINT SDBAR;

*/ERROR GENERATING PROCESSES FOR THE EDUCATION REGISTER/*;
*/ERROR GENERATING PROCESSES FOR THE EDUCATION REGISTER/*;
*/ERROR GENERATING PROCESSES FOR THE EDUCATION REGISTER/*;

    */CREATE THE MATRIX OF RAW INFORMATION FROM THE EVALUATION OF "UTB. REGISTRET"/*;
    */CREATE THE MATRIX OF RAW INFORMATION FROM THE EVALUATION OF "UTB. REGISTRET"/*;
    */CREATE THE MATRIX OF RAW INFORMATION FROM THE EVALUATION OF "UTB. REGISTRET"/*;

        */FIRST THE MATRIX FOR INDIVIDUALS BORN IN SWEDEN AGE:16-64/*;
        */FIRST THE MATRIX FOR INDIVIDUALS BORN IN SWEDEN AGE:16-64/*;
        */FIRST THE MATRIX FOR INDIVIDUALS BORN IN SWEDEN AGE:16-64/*;

TEMPR1=671928||12785||80978||776||0||419||0;
TEMPR2=8981||678408||62860||9217||793||0||0;
TEMPR3=79634||110981||1359125||50646||15333||2061||0;
TEMPR4=13255||15589||71799||465575||13579||4064||357;
TEMPR5=1621||5484||28660||58068||457495||16299||0;
TEMPR6=444||431||2433||15658||23385||403222||777;
TEMPR7=0||0||0||0||0||3751||20085;

        */CREATE THE DENOMINATORS NEEDED TO TRANSFORM TEMPRi INTO FREQUENCIES:ROWTOT-U.S./*;
        */CREATE THE DENOMINATORS NEEDED TO TRANSFORM TEMPRi INTO FREQUENCIES:ROWTOT-U.S./*;
        */CREATE THE DENOMINATORS NEEDED TO TRANSFORM TEMPRi INTO FREQUENCIES:ROWTOT-U.S./*;

DEN1=766855;
DEN2=764080-3821;
DEN3=1621937-4158;
DEN4=584218;
DEN5=575375-7748;
DEN6=446350;
DEN7=27994-4158;

R1=INV(DEN1)*TEMPR1;
R2=INV(DEN2)*TEMPR2;
R3=INV(DEN3)*TEMPR3;
R4=INV(DEN4)*TEMPR4;
R5=INV(DEN5)*TEMPR5;
R6=INV(DEN6)*TEMPR6;
R7=INV(DEN7)*TEMPR7;

R=R1//R2//R3//R4//R5//R6//R7;

PRINT R;

        */DEFINE THE PROBABILITY THAT AN IND. WHOSE TRUE CATEGORY IS J
        IS CLASSIFIED IN CATEGORY K/*;
        */DEFINE THE PROBABILITY THAT AN IND. WHOSE TRUE CATEGORY IS J
        IS CLASSIFIED IN CATEGORY K/*;
        */DEFINE THE PROBABILITY THAT AN IND. WHOSE TRUE CATEGORY IS J
        IS CLASSIFIED IN CATEGORY K/*;
        */DEFINE THE PROBABILITY THAT AN IND. WHOSE TRUE CATEGORY IS J
        IS CLASSIFIED IN CATEGORY K/*;

        */START FIRST ERROR GENERATING PROCESS/*;
        */START FIRST ERROR GENERATING PROCESS/*;
        */START FIRST ERROR GENERATING PROCESS/*;

P=R;

        */START THE SECOND ERROR GENERATING PROCESS - NO ERROR/*;
        */START THE SECOND ERROR GENERATING PROCESS - NO ERROR/*;
        */START THE SECOND ERROR GENERATING PROCESS - NO ERROR/*;

P=I(7);


        */CREATE THE KAPPA-MATRIX OF FULLER/*;
        */CREATE THE KAPPA-MATRIX OF FULLER/*;
        */CREATE THE KAPPA-MATRIX OF FULLER/*;


PT=P`;

PRINT P;
PRINT PT;

    */CREATE ALSO THE COLUMNS OF THE KAPPA-MATRIX/*;

PT1=PT[1:7,1];
PT2=PT[1:7,2];
PT3=PT[1:7,3];
PT4=PT[1:7,4];
PT5=PT[1:7,5];
PT6=PT[1:7,6];
PT7=PT[1:7,7];

XT=INV(PT)*XOBS`;

    */CREATE MJUHAT OF FULLER/*;
    */CREATE MJUHAT OF FULLER/*;
    */CREATE MJUHAT OF FULLER/*;

MJUHAT=INV(PT)*ABAR`;

ABART=ABAR`;

PRINT MJUHAT;

PRINT ABART;

OMEG11=DIAG(PT1)-PT1*PT1`;
OMEG22=DIAG(PT2)-PT2*PT2`;
OMEG33=DIAG(PT3)-PT3*PT3`;
OMEG44=DIAG(PT4)-PT4*PT4`;
OMEG55=DIAG(PT5)-PT5*PT5`;
OMEG66=DIAG(PT6)-PT6*PT6`;
OMEG77=DIAG(PT7)-PT7*PT7`;

PRINT OMEG11;
PRINT OMEG22;
PRINT OMEG33;
PRINT OMEG44;
PRINT OMEG55;
PRINT OMEG66;
PRINT OMEG77;

ABAR1=ABART[1,1];
ABAR2=ABART[2,1];
ABAR3=ABART[3,1];
ABAR4=ABART[4,1];
ABAR5=ABART[5,1];
ABAR6=ABART[6,1];
ABAR7=ABART[7,1];

MJU1=MJUHAT[1,1];
MJU2=MJUHAT[2,1];
MJU3=MJUHAT[3,1];
MJU4=MJUHAT[4,1];
MJU5=MJUHAT[5,1];
MJU6=MJUHAT[6,1];
MJU7=MJUHAT[7,1];

SIGu11=(MJU1/ABAR1)*INV(PT)*OMEG11*INV(PT)`;
SIGu22=(MJU2/ABAR2)*INV(PT)*OMEG22*INV(PT)`;
SIGu33=(MJU3/ABAR3)*INV(PT)*OMEG33*INV(PT)`;
SIGu44=(MJU4/ABAR4)*INV(PT)*OMEG44*INV(PT)`;
SIGu55=(MJU5/ABAR5)*INV(PT)*OMEG55*INV(PT)`;
SIGu66=(MJU6/ABAR6)*INV(PT)*OMEG66*INV(PT)`;
SIGu77=(MJU7/ABAR7)*INV(PT)*OMEG77*INV(PT)`;

PRINT SIGu11;
PRINT SIGu22;
PRINT SIGu33;
PRINT SIGu44;
PRINT SIGu55;
PRINT SIGu66;
PRINT SIGu77;

Q1=(MJU1/ABAR1);
Q2=(MJU2/ABAR2);
Q3=(MJU3/ABAR3);
Q4=(MJU4/ABAR4);
Q5=(MJU5/ABAR5);
Q6=(MJU6/ABAR6);
Q7=(MJU7/ABAR7);

PRINT Q1;
PRINT Q2;
PRINT Q3;
PRINT Q4;
PRINT Q5;
PRINT Q6;
PRINT Q7;

ALFA=INV(XT*XT`-NSLLS1*SIGu11-NSLLS2*SIGu22-NSLLS3*SIGu33-NSLLS4*SIGu44-
NSLLS5*SIGu55-NSLLS6*SIGu66-NSLLS7*SIGu77)*XT*S;

PRINT ALFA;

          */A TEST TO SEE THAT THE ADJUSTED "X`*X" MATRIX IS OK/*;
          */A TEST TO SEE THAT THE ADJUSTED "X`*X" MATRIX IS OK/*;
          */A TEST TO SEE THAT THE ADJUSTED "X`*X" MATRIX IS OK/*;

TEST0=VECDIAG((XT*XT`-NSLLS1*SIGu11-NSLLS2*SIGu22-NSLLS3*SIGu33-NSLLS4*SIGu44-
NSLLS5*SIGu55-NSLLS6*SIGu66-NSLLS7*SIGu77));
PRINT TEST0;
MJUHATN=NSLLS*MJUHAT;
PRINT MJUHATN;
ISOK0=TEST0-MJUHATN;
PRINT ISOK0;

        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;
        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;
        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;

VHAT=S-XT`*ALFA;

VHBIG=VHAT||VHAT||VHAT||VHAT||VHAT||VHAT||VHAT;

XVHAT=XT`#VHBIG;

XVT=XVHAT`;

SIGUU=SIGu11*(-1)*ALFA||SIGu22*(-1)*ALFA||SIGu33*(-1)*ALFA||SIGu44*(-1)*ALFA||
SIGu55*(-1)*ALFA||SIGu66*(-1)*ALFA||SIGu77*(-1)*ALFA;

PRINT SIGUU;

PICK=SIGUU*XOBS`;

DHATT=XVT-PICK;

GHAT=(1/(NSLLS-KSLLS))*DHATT*DHATT`;

PRINT GHAT;

VALFA=(1/NSLLS)*
INV((1/NSLLS)*(XT*XT`-NSLLS1*SIGu11-NSLLS2*SIGu22-NSLLS3*SIGu33-NSLLS4*SIGu44-NSLLS5*SIGu55-
NSLLS6*SIGu66-NSLLS7*SIGu77))*
GHAT*
INV((1/NSLLS)*(XT*XT`-NSLLS1*SIGu11-NSLLS2*SIGu22-NSLLS3*SIGu33-NSLLS4*SIGu44-NSLLS5*SIGu55-
NSLLS6*SIGu66-NSLLS7*SIGu77));

PRINT VALFA;

            */THE STANDARD ERRORS OF EACH ELEMENT IN ALFA/*;
            */THE STANDARD ERRORS OF EACH ELEMENT IN ALFA/*;
            */THE STANDARD ERRORS OF EACH ELEMENT IN ALFA/*;

SEALFA=SQRT(VECDIAG(VALFA));
PRINT SEALFA;


        */PICK OUT THE DIFFERENCE IN YEARS OF SCHOOLING BETWEEN SUCCESIVE EDUCATIONAL LEVELS/*;
        */PICK OUT THE DIFFERENCE IN YEARS OF SCHOOLING BETWEEN SUCCESIVE EDUCATIONAL LEVELS/*;
        */PICK OUT THE DIFFERENCE IN YEARS OF SCHOOLING BETWEEN SUCCESIVE EDUCATIONAL LEVELS/*;

ALFA_21=ALFA[2,1]-ALFA[1,1];
ALFA_32=ALFA[3,1]-ALFA[2,1];
ALFA_43=ALFA[4,1]-ALFA[3,1];
ALFA_54=ALFA[5,1]-ALFA[4,1];
ALFA_65=ALFA[6,1]-ALFA[5,1];
ALFA_76=ALFA[7,1]-ALFA[6,1];

PRINT ALFA_21;
PRINT ALFA_32;
PRINT ALFA_43;
PRINT ALFA_54;
PRINT ALFA_65;
PRINT ALFA_76;

ALFA_=ALFA_21//ALFA_32//ALFA_43//ALFA_54//ALFA_65//ALFA_76;

PRINT ALFA_;

            */NOW CONSTRUCT THE VARIANCE MATRIX OF ALFA_/*;
            */NOW CONSTRUCT THE VARIANCE MATRIX OF ALFA_/*;
            */NOW CONSTRUCT THE VARIANCE MATRIX OF ALFA_/*;

   */FIRST, CONSTRUCT THE VARIANCE OF EACH ELEMENT IN ALFA_ij/*;
   */FIRST, CONSTRUCT THE VARIANCE OF EACH ELEMENT IN ALFA_ij/*;
   */FIRST, CONSTRUCT THE VARIANCE OF EACH ELEMENT IN ALFA_ij/*;


VALFA_21=VALFA[2,2]+VALFA[1,1]-2*VALFA[2,1];
VALFA_32=VALFA[3,3]+VALFA[2,2]-2*VALFA[3,2];
VALFA_43=VALFA[4,4]+VALFA[3,3]-2*VALFA[4,3];
VALFA_54=VALFA[5,5]+VALFA[4,4]-2*VALFA[5,4];
VALFA_65=VALFA[6,6]+VALFA[5,5]-2*VALFA[6,5];
VALFA_76=VALFA[7,7]+VALFA[6,6]-2*VALFA[7,6];


               */SECOND, THE COVARIANCES IN ALFA_/*;
               */SECOND, THE COVARIANCES IN ALFA_/*;
               */SECOND, THE COVARIANCES IN ALFA_/*;


CA_2132=VALFA[2,3]-VALFA[2,2]-VALFA[1,3]+VALFA[1,2];
CA_2143=VALFA[2,4]-VALFA[2,3]-VALFA[1,4]+VALFA[1,3];
CA_2154=VALFA[2,5]-VALFA[2,4]-VALFA[1,5]+VALFA[1,4];
CA_2165=VALFA[2,6]-VALFA[2,5]-VALFA[1,6]+VALFA[1,5];
CA_2176=VALFA[2,7]-VALFA[2,6]-VALFA[1,7]+VALFA[1,6];

CA_3221=VALFA[3,2]-VALFA[3,1]-VALFA[2,2]+VALFA[2,1];
CA_3243=VALFA[3,4]-VALFA[3,3]-VALFA[2,4]+VALFA[2,3];
CA_3254=VALFA[3,5]-VALFA[3,4]-VALFA[2,5]+VALFA[2,4];
CA_3265=VALFA[3,6]-VALFA[3,5]-VALFA[2,6]+VALFA[2,5];
CA_3276=VALFA[3,7]-VALFA[3,6]-VALFA[2,7]+VALFA[2,6];

CA_4321=VALFA[4,2]-VALFA[4,1]-VALFA[3,2]+VALFA[3,1];
CA_4332=VALFA[4,3]-VALFA[4,2]-VALFA[3,3]+VALFA[3,2];
CA_4354=VALFA[4,5]-VALFA[4,4]-VALFA[3,5]+VALFA[3,4];
CA_4365=VALFA[4,6]-VALFA[4,5]-VALFA[3,6]+VALFA[3,5];
CA_4376=VALFA[4,7]-VALFA[4,6]-VALFA[3,7]+VALFA[3,6];

CA_5421=VALFA[5,2]-VALFA[5,1]-VALFA[4,2]+VALFA[4,1];
CA_5432=VALFA[5,3]-VALFA[5,2]-VALFA[4,3]+VALFA[4,2];
CA_5443=VALFA[5,4]-VALFA[5,3]-VALFA[4,4]+VALFA[4,3];
CA_5465=VALFA[5,6]-VALFA[5,5]-VALFA[4,6]+VALFA[4,5];
CA_5476=VALFA[5,7]-VALFA[5,6]-VALFA[4,7]+VALFA[4,6];

CA_6521=VALFA[6,2]-VALFA[6,1]-VALFA[5,2]+VALFA[5,1];
CA_6532=VALFA[6,3]-VALFA[6,2]-VALFA[5,3]+VALFA[5,2];
CA_6543=VALFA[6,4]-VALFA[6,3]-VALFA[5,4]+VALFA[5,3];
CA_6554=VALFA[6,5]-VALFA[6,4]-VALFA[5,5]+VALFA[5,4];
CA_6576=VALFA[6,7]-VALFA[6,6]-VALFA[5,7]+VALFA[5,7];

CA_7621=VALFA[7,2]-VALFA[7,1]-VALFA[6,2]+VALFA[6,1];
CA_7632=VALFA[7,3]-VALFA[7,2]-VALFA[6,3]+VALFA[6,2];
CA_7643=VALFA[7,4]-VALFA[7,3]-VALFA[6,4]+VALFA[6,3];
CA_7654=VALFA[7,5]-VALFA[7,4]-VALFA[6,5]+VALFA[6,4];
CA_7665=VALFA[7,6]-VALFA[7,5]-VALFA[6,6]+VALFA[6,5];


            */THE ROWS OF THE VARIANCE MATRIX/*;
            */THE ROWS OF THE VARIANCE MATRIX/*;
            */THE ROWS OF THE VARIANCE MATRIX/*;

VA_R1=VALFA_21||CA_2132||CA_2143||CA_2154||CA_2165||CA_2176;
VA_R2=CA_3221||VALFA_32||CA_3243||CA_3254||CA_3265||CA_3276;
VA_R3=CA_4321||CA_4332||VALFA_43||CA_4354||CA_4365||CA_4376;
VA_R4=CA_5421||CA_5432||CA_5443||VALFA_54||CA_5465||CA_5476;
VA_R5=CA_6521||CA_6532||CA_6543||CA_6554||VALFA_65||CA_7665;
VA_R6=CA_7621||CA_7632||CA_7643||CA_7654||CA_7665||VALFA_76;

                    */THE COMPLETE MATRIX/*;
                    */THE COMPLETE MATRIX/*;
                    */THE COMPLETE MATRIX/*;


VALFA_=VA_R1//VA_R2//VA_R3//VA_R4//VA_R5//VA_R6;

PRINT VALFA_;

            */THE CORRESPONDING STANDARD ERRORS/*;
            */THE CORRESPONDING STANDARD ERRORS/*;
            */THE CORRESPONDING STANDARD ERRORS/*;


SALFA_=SQRT(VECDIAG(VALFA_));

PRINT SALFA_;


          */THE EARNINGS EQUATION FOR THE SLLS/*;
          */THE EARNINGS EQUATION FOR THE SLLS/*;
          */THE EARNINGS EQUATION FOR THE SLLS/*;

          */CREATE THE VARIANCE-COVARIANCE MATRIX FOR THE MEASUREMENT ERRORS/*;
          */CREATE THE VARIANCE-COVARIANCE MATRIX FOR THE MEASUREMENT ERRORS/*;
          */CREATE THE VARIANCE-COVARIANCE MATRIX FOR THE MEASUREMENT ERRORS/*;

ZERO1=J(7,3,0);
ZERO2=J(3,10,0);

SIGu_11=SIGu11||ZERO1;
SIGu11=SIGu_11//ZERO2;

SIGu_22=SIGu22||ZERO1;
SIGu22=SIGu_22//ZERO2;

SIGu_33=SIGu33||ZERO1;
SIGu33=SIGu_33//ZERO2;

SIGu_44=SIGu44||ZERO1;
SIGu44=SIGu_44//ZERO2;

SIGu_55=SIGu55||ZERO1;
SIGu55=SIGu_55//ZERO2;

SIGu_66=SIGu66||ZERO1;
SIGu66=SIGu_66//ZERO2;

SIGu_77=SIGu77||ZERO1;
SIGu77=SIGu_77//ZERO2;

X_CONT=XT`||AGE||AGEQ||SEXE;

TH_SLLS=INV(X_CONT`*X_CONT-
NSLLS1*SIGu11-NSLLS2*SIGu22-NSLLS3*SIGu33-NSLLS4*SIGu44-
NSLLS5*SIGu55-NSLLS6*SIGu66-NSLLS7*SIGu77)*X_CONT`*LINC;

PRINT TH_SLLS;

          */A TEST TO SEE THAT THE ADJUSTED "X`*X" MATRIX IS OK/*;
          */A TEST TO SEE THAT THE ADJUSTED "X`*X" MATRIX IS OK/*;
          */A TEST TO SEE THAT THE ADJUSTED "X`*X" MATRIX IS OK/*;

TEST1_1=VECDIAG((X_CONT`*X_CONT-NSLLS1*SIGu11-NSLLS2*SIGu22-NSLLS3*SIGu33-NSLLS4*SIGu44-
NSLLS5*SIGu55-NSLLS6*SIGu66-NSLLS7*SIGu77));
TEST1=TEST1_1[1:7,1];
PRINT TEST1;
MJUHATN=NSLLS*MJUHAT;
PRINT MJUHATN;
ISOK1=TEST1-MJUHATN;
PRINT ISOK1;

*/BESIDE ROUNDING ERRORS IN THE COMPUTATION OF THE INV(MATRIX): TEST1=MJUHATN IF ADJUSTMENT OK/;

        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYSLLS"/*;
        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYSLLS"/*;
        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYSLLS"/*;

VHATSLLS=LINC-X_CONT*TH_SLLS;

VHBIG=VHATSLLS||VHATSLLS||VHATSLLS||VHATSLLS||VHATSLLS||VHATSLLS||VHATSLLS||VHATSLLS||VHATSLLS||VHATSLLS;

XVHAT=X_CONT#VHBIG;

TH_SLLS_=TH_SLLS[1:7,1];

PRINT TH_SLLS_;

SIGUULS=SIGu11*(-1)*TH_SLLS||SIGu22*(-1)*TH_SLLS||SIGu33*(-1)*TH_SLLS||SIGu44*(-1)*TH_SLLS||
SIGu55*(-1)*TH_SLLS||SIGu66*(-1)*TH_SLLS||SIGu77*(-1)*TH_SLLS;

PRINT SIGUULS;

PICKLS=SIGUULS*XOBS`;

DHATTLS=XVHAT`-PICKLS;

GHATLS=(1/(NSLLS-KSLLS-3))*DHATTLS*DHATTLS`;

PRINT GHATLS;

VSLLS=(1/NSLLS)*
INV((1/NSLLS)*(X_CONT`*X_CONT-
NSLLS1*SIGu11-NSLLS2*SIGu22-NSLLS3*SIGu33-NSLLS4*SIGu44-
NSLLS5*SIGu55-NSLLS6*SIGu66-NSLLS7*SIGu77))*
GHATLS*
INV((1/NSLLS)*(X_CONT`*X_CONT-
NSLLS1*SIGu11-NSLLS2*SIGu22-NSLLS3*SIGu33-NSLLS4*SIGu44-
NSLLS5*SIGu55-NSLLS6*SIGu66-NSLLS7*SIGu77));

PRINT VSLLS;

            */THE STANDARD ERRORS OF EACH ELEMENT IN BSLLS/*;
            */THE STANDARD ERRORS OF EACH ELEMENT IN BSLLS/*;
            */THE STANDARD ERRORS OF EACH ELEMENT IN BSLLS/*;

SESLLS=SQRT(VECDIAG(VSLLS));
PRINT SESLLS;

        */NOW START TO CONSTRUCT WAGE PREMIUMS RELATIVE TO THE LOWEST EDUCATIONAL LEVELS/*;
        */NOW START TO CONSTRUCT WAGE PREMIUMS RELATIVE TO THE LOWEST EDUCATIONAL LEVELS/*;
        */NOW START TO CONSTRUCT WAGE PREMIUMS RELATIVE TO THE LOWEST EDUCATIONAL LEVELS/*;

THSLLS1=TH_SLLS[1,1];
THSLLS2=TH_SLLS[2,1];
THSLLS3=TH_SLLS[3,1];
THSLLS4=TH_SLLS[4,1];
THSLLS5=TH_SLLS[5,1];
THSLLS6=TH_SLLS[6,1];
THSLLS7=TH_SLLS[7,1];


            */THE WAGE PREMIUMS RELATIVE TO CATEGORY 1/*;
            */THE WAGE PREMIUMS RELATIVE TO CATEGORY 1/*;
            */THE WAGE PREMIUMS RELATIVE TO CATEGORY 1/*;


WP21SLLS=THSLLS2-THSLLS1;
WP31SLLS=THSLLS3-THSLLS1;
WP41SLLS=THSLLS4-THSLLS1;
WP51SLLS=THSLLS5-THSLLS1;
WP61SLLS=THSLLS6-THSLLS1;
WP71SLLS=THSLLS7-THSLLS1;

WPSLLS=WP21SLLS//WP31SLLS//WP41SLLS//WP51SLLS//WP61SLLS//WP71SLLS;

PRINT WPSLLS;

     */CONSTRUCT THE VARIANCE OF EACH WPi/*;
     */CONSTRUCT THE VARIANCE OF EACH WPi/*;
     */CONSTRUCT THE VARIANCE OF EACH WPi/*;

VW21SLLS=VSLLS[2,2]+VSLLS[1,1]-2*VSLLS[2,1];
VW31SLLS=VSLLS[3,3]+VSLLS[1,1]-2*VSLLS[3,1];
VW41SLLS=VSLLS[4,4]+VSLLS[1,1]-2*VSLLS[4,1];
VW51SLLS=VSLLS[5,5]+VSLLS[1,1]-2*VSLLS[5,1];
VW61SLLS=VSLLS[6,6]+VSLLS[1,1]-2*VSLLS[6,1];
VW71SLLS=VSLLS[7,7]+VSLLS[1,1]-2*VSLLS[7,1];

    */THE CORRESPONDING STANDARD ERRORS/*;
    */THE CORRESPONDING STANDARD ERRORS/*;
    */THE CORRESPONDING STANDARD ERRORS/*;

SEWPSLLS=
SQRT(VW21SLLS)//SQRT(VW31SLLS)//SQRT(VW41SLLS)//SQRT(VW51SLLS)//SQRT(VW61SLLS)//SQRT(VW71SLLS);
PRINT SEWPSLLS;

     */CONSTRUCT THE DIFFERENCE BETWEEN WAGE PREMIUM OF EACH LEVEL AND THE NEXT-TO-LOWER LEVEL/;
     */CONSTRUCT THE DIFFERENCE BETWEEN WAGE PREMIUM OF EACH LEVEL AND THE NEXT-TO-LOWER LEVEL/;
     */CONSTRUCT THE DIFFERENCE BETWEEN WAGE PREMIUM OF EACH LEVEL AND THE NEXT-TO-LOWER LEVEL/;

THLS2_1=THSLLS2-THSLLS1;
THLS3_2=THSLLS3-THSLLS2;
THLS4_3=THSLLS4-THSLLS3;
THLS5_4=THSLLS5-THSLLS4;
THLS6_5=THSLLS6-THSLLS5;
THLS7_6=THSLLS7-THSLLS6;

DTHSLLS=THLS2_1||THLS3_2||THLS4_3||THLS5_4||THLS6_5||THLS7_6;

PRINT DTHSLLS;

             */THE VARIANCE MATRIX OF DTHSLLS/*;
             */THE VARIANCE MATRIX OF DTHSLLS/*;
             */THE VARIANCE MATRIX OF DTHSLLS/*;


     */FIRST CONSTRUCT THE VARIANCE OF EACH THLSi_i-1/*;
     */FIRST CONSTRUCT THE VARIANCE OF EACH THLSi_i-1/*;
     */FIRST CONSTRUCT THE VARIANCE OF EACH THLSi_i-1/*;

VTH2_1=VSLLS[2,2]+VSLLS[1,1]-2*VSLLS[2,1];
VTH3_2=VSLLS[3,3]+VSLLS[2,2]-2*VSLLS[3,2];
VTH4_3=VSLLS[4,4]+VSLLS[3,3]-2*VSLLS[4,3];
VTH5_4=VSLLS[5,5]+VSLLS[4,4]-2*VSLLS[5,4];
VTH6_5=VSLLS[6,6]+VSLLS[5,5]-2*VSLLS[6,5];
VTH7_6=VSLLS[7,7]+VSLLS[6,6]-2*VSLLS[7,6];

    */SECOND CONSTRUCT THE COVARIANCES DTHSLLSi_ij,DTHSLLSj_ji/*;
    */SECOND CONSTRUCT THE COVARIANCES DTHSLLSi_ij,DTHSLLSj_ji/*;
    */SECOND CONSTRUCT THE COVARIANCES DTHSLLSi_ij,DTHSLLSj_ji/*;

CLS2132=VSLLS[2,3]-VSLLS[2,2]-VSLLS[1,3]+VSLLS[1,2];
CLS2143=VSLLS[2,4]-VSLLS[2,3]-VSLLS[1,4]+VSLLS[1,3];
CLS2154=VSLLS[2,5]-VSLLS[2,4]-VSLLS[1,5]+VSLLS[1,4];
CLS2165=VSLLS[2,6]-VSLLS[2,5]-VSLLS[1,6]+VSLLS[1,5];
CLS2176=VSLLS[2,7]-VSLLS[2,6]-VSLLS[1,7]+VSLLS[1,6];

CLS3221=VSLLS[3,2]-VSLLS[3,1]-VSLLS[2,2]+VSLLS[2,1];
CLS3243=VSLLS[3,4]-VSLLS[3,3]-VSLLS[2,4]+VSLLS[2,3];
CLS3254=VSLLS[3,5]-VSLLS[3,4]-VSLLS[2,5]+VSLLS[2,4];
CLS3265=VSLLS[3,6]-VSLLS[3,5]-VSLLS[2,6]+VSLLS[2,5];
CLS3276=VSLLS[3,7]-VSLLS[3,6]-VSLLS[2,7]+VSLLS[2,6];

CLS4321=VSLLS[4,2]-VSLLS[4,1]-VSLLS[3,2]+VSLLS[3,1];
CLS4332=VSLLS[4,3]-VSLLS[4,2]-VSLLS[3,3]+VSLLS[3,2];
CLS4354=VSLLS[4,5]-VSLLS[4,4]-VSLLS[3,5]+VSLLS[3,4];
CLS4365=VSLLS[4,6]-VSLLS[4,5]-VSLLS[3,6]+VSLLS[3,5];
CLS4376=VSLLS[4,7]-VSLLS[4,6]-VSLLS[3,7]+VSLLS[3,6];

CLS5421=VSLLS[5,2]-VSLLS[5,1]-VSLLS[4,2]+VSLLS[4,1];
CLS5432=VSLLS[5,3]-VSLLS[5,2]-VSLLS[4,3]+VSLLS[4,2];
CLS5443=VSLLS[5,4]-VSLLS[5,3]-VSLLS[4,4]+VSLLS[4,3];
CLS5465=VSLLS[5,6]-VSLLS[5,5]-VSLLS[4,6]+VSLLS[4,5];
CLS5476=VSLLS[5,7]-VSLLS[5,6]-VSLLS[4,7]+VSLLS[4,6];

CLS6521=VSLLS[6,2]-VSLLS[6,1]-VSLLS[5,2]+VSLLS[5,1];
CLS6532=VSLLS[6,3]-VSLLS[6,2]-VSLLS[5,3]+VSLLS[5,2];
CLS6543=VSLLS[6,4]-VSLLS[6,3]-VSLLS[5,4]+VSLLS[5,3];
CLS6554=VSLLS[6,5]-VSLLS[6,4]-VSLLS[5,5]+VSLLS[5,4];
CLS6576=VSLLS[6,7]-VSLLS[6,6]-VSLLS[5,7]+VSLLS[5,6];

CLS7621=VSLLS[7,2]-VSLLS[7,1]-VSLLS[6,2]+VSLLS[6,1];
CLS7632=VSLLS[7,3]-VSLLS[7,2]-VSLLS[6,3]+VSLLS[6,2];
CLS7643=VSLLS[7,4]-VSLLS[7,3]-VSLLS[6,4]+VSLLS[6,3];
CLS7654=VSLLS[7,5]-VSLLS[7,4]-VSLLS[6,5]+VSLLS[6,4];
CLS7665=VSLLS[7,6]-VSLLS[7,5]-VSLLS[6,6]+VSLLS[6,5];

          */THE ROWS OF THE MATRIX/*;
          */THE ROWS OF THE MATRIX/*;
          */THE ROWS OF THE MATRIX/*;

VDTH_R1=VTH2_1||CLS2132||CLS2143||CLS2154||CLS2165||CLS2176;
VDTH_R2=CLS3221||VTH3_2||CLS3243||CLS3254||CLS3265||CLS3276;
VDTH_R3=CLS4321||CLS4332||VTH4_3||CLS4354||CLS4365||CLS4376;
VDTH_R4=CLS5421||CLS5432||CLS5443||VTH5_4||CLS5465||CLS5476;
VDTH_R5=CLS6521||CLS6532||CLS6543||CLS6554||VTH6_5||CLS6576;
VDTH_R6=CLS7621||CLS7632||CLS7643||CLS7654||CLS7665||VTH7_6;

            */THE COMPLETE MATRIX/*;
            */THE COMPLETE MATRIX/*;
            */THE COMPLETE MATRIX/*;


VDTHLS=VDTH_R1//VDTH_R2//VDTH_R3//VDTH_R4//VDTH_R5//VDTH_R6;
PRINT VDTHLS;

                  */THE STANDARD ERRORS/*;
                  */THE STANDARD ERRORS/*;
                  */THE STANDARD ERRORS/*;

SEDTHLS=SQRT(VECDIAG(VDTHLS));
PRINT SEDTHLS;

         */THE RETURNS TO ADDITIONAL YEARS OF SCHOOLING AT EACH LEVEL/*;
         */THE RETURNS TO ADDITIONAL YEARS OF SCHOOLING AT EACH LEVEL/*;
         */THE RETURNS TO ADDITIONAL YEARS OF SCHOOLING AT EACH LEVEL/*;

BETALS2=THLS2_1/ALFA_21;
BETALS3=THLS3_2/ALFA_32;
BETALS4=THLS4_3/ALFA_43;
BETALS5=THLS5_4/ALFA_54;
BETALS6=THLS6_5/ALFA_65;
BETALS7=THLS7_6/ALFA_76;

BETALS=BETALS2//BETALS3//BETALS4//BETALS5//BETALS6//BETALS7;
PRINT BETALS;

           */THE VARIANCE MATRIX OF EACH BETALSi i = 2, 3, ..., 7/*;
           */THE VARIANCE MATRIX OF EACH BETALSi i = 2, 3, ..., 7/*;
           */THE VARIANCE MATRIX OF EACH BETALSi i = 2, 3, ..., 7/*;

VBLS2=(VDTHLS[1,1]/(ALFA_21**2))+((THLS2_1**2)*VALFA_[1,1])/((ALFA_21**2)*(ALFA_21**2));
VBLS3=(VDTHLS[2,2]/(ALFA_32**2))+((THLS3_2**2)*VALFA_[2,2])/((ALFA_32**2)*(ALFA_32**2));
VBLS4=(VDTHLS[3,3]/(ALFA_43**2))+((THLS4_3**2)*VALFA_[3,3])/((ALFA_43**2)*(ALFA_43**2));
VBLS5=(VDTHLS[4,4]/(ALFA_54**2))+((THLS5_4**2)*VALFA_[4,4])/((ALFA_54**2)*(ALFA_54**2));
VBLS6=(VDTHLS[5,5]/(ALFA_65**2))+((THLS6_5**2)*VALFA_[5,5])/((ALFA_65**2)*(ALFA_65**2));
VBLS7=(VDTHLS[6,6]/(ALFA_76**2))+((THLS7_6**2)*VALFA_[6,6])/((ALFA_76**2)*(ALFA_76**2));

PRINT VBLS2;
PRINT VBLS3;
PRINT VBLS4;
PRINT VBLS5;
PRINT VBLS6;
PRINT VBLS7;

          */THE CORRESPONDING STANDARD ERRORS/*;
          */THE CORRESPONDING STANDARD ERRORS/*;
          */THE CORRESPONDING STANDARD ERRORS/*;

SEBETALS=
SQRT(VBLS2)//SQRT(VBLS3)//SQRT(VBLS4)//SQRT(VBLS5)//SQRT(VBLS6)//SQRT(VBLS7);

PRINT SEBETALS;

    */WEIGH THE SEPARATE ESTIMATES TOGETHER WITH THE OLS WEIGHTING FUNCTION/*;
    */WEIGH THE SEPARATE ESTIMATES TOGETHER WITH THE OLS WEIGHTING FUNCTION/*;
    */WEIGH THE SEPARATE ESTIMATES TOGETHER WITH THE OLS WEIGHTING FUNCTION/*;


                                            */FIRST THE OLS-WEIGHTS/*;
                                            */FIRST THE OLS-WEIGHTS/*;
                                            */FIRST THE OLS-WEIGHTS/*;

NLS1=NSLLS*(MJUHAT[1,1]);
NLS2=NSLLS*(MJUHAT[1,1]+MJUHAT[2,1]);
NLS3=NSLLS*(MJUHAT[1,1]+MJUHAT[2,1]+MJUHAT[3,1]);
NLS4=NSLLS*(MJUHAT[1,1]+MJUHAT[2,1]+MJUHAT[3,1]+MJUHAT[4,1]);
NLS5=NSLLS*(MJUHAT[1,1]+MJUHAT[2,1]+MJUHAT[3,1]+MJUHAT[4,1]+MJUHAT[5,1]);
NLS6=NSLLS*(MJUHAT[1,1]+MJUHAT[2,1]+MJUHAT[3,1]+MJUHAT[4,1]+MJUHAT[5,1]+MJUHAT[6,1]);
NLS7=NSLLS*(MJUHAT[1,1]+MJUHAT[2,1]+MJUHAT[3,1]+MJUHAT[4,1]+MJUHAT[5,1]+MJUHAT[6,1]+
MJUHAT[7,1]);

PRINT NLS1;
PRINT NLS2;
PRINT NLS3;
PRINT NLS4;
PRINT NLS5;
PRINT NLS6;
PRINT NLS7;
PRINT NSLLS;

WSLLS1=
(NLS1*((NSLLS-NLS1)*ALFA_21+(NSLLS-NLS2)*ALFA_32+(NSLLS-
NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76))*ALFA_21/

((NLS1*((NSLLS-NLS1)*ALFA_21+(NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76))*ALFA_21+
 (NLS2*((NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS2)*(NLS1*ALFA_21))*ALFA_32+
 (NLS3*((NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS
-NLS3)*(NLS1*ALFA_21+NLS2*ALFA_32))*ALFA_43+
 (NLS4*((NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS4)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43))*ALFA_54+
 (NLS5*((NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS5)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54))*ALFA_65+
 (NLS6*((NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS6)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54+NLS5*ALFA_65))*ALFA_76);

PRINT WSLLS1;

WSLLS2=
(NLS2*((NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+
(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS2)*(NLS1*ALFA_21))*ALFA_32/

((NLS1*((NSLLS-NLS1)*ALFA_21+(NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76))*ALFA_21+
 (NLS2*((NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS2)*(NLS1*ALFA_21))*ALFA_32+
 (NLS3*((NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS
-NLS3)*(NLS1*ALFA_21+NLS2*ALFA_32))*ALFA_43+
 (NLS4*((NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS4)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43))*ALFA_54+
 (NLS5*((NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS5)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54))*ALFA_65+
 (NLS6*((NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS6)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54+NLS5*ALFA_65))*ALFA_76);


PRINT WSLLS2;

WSLLS3=(NLS3*((NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+
(NSLLS-NLS3)*(NLS1*ALFA_21+NLS2*ALFA_32))*ALFA_43/

((NLS1*((NSLLS-NLS1)*ALFA_21+(NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76))*ALFA_21+
 (NLS2*((NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS2)*(NLS1*ALFA_21))*ALFA_32+
 (NLS3*((NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS
-NLS3)*(NLS1*ALFA_21+NLS2*ALFA_32))*ALFA_43+
 (NLS4*((NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS4)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43))*ALFA_54+
 (NLS5*((NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS5)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54))*ALFA_65+
 (NLS6*((NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS6)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54+NLS5*ALFA_65))*ALFA_76);


PRINT WSLLS3;

WSLLS4=(NLS4*((NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+
(NSLLS-NLS4)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43))*ALFA_54/

((NLS1*((NSLLS-NLS1)*ALFA_21+(NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76))*ALFA_21+
 (NLS2*((NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS2)*(NLS1*ALFA_21))*ALFA_32+
 (NLS3*((NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS
-NLS3)*(NLS1*ALFA_21+NLS2*ALFA_32))*ALFA_43+
 (NLS4*((NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS4)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43))*ALFA_54+
 (NLS5*((NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS5)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54))*ALFA_65+
 (NLS6*((NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS6)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54+NLS5*ALFA_65))*ALFA_76);


PRINT WSLLS4;

WSLLS5=(NLS5*((NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS5)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54))*ALFA_65/

((NLS1*((NSLLS-NLS1)*ALFA_21+(NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76))*ALFA_21+
 (NLS2*((NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS2)*(NLS1*ALFA_21))*ALFA_32+
 (NLS3*((NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS
-NLS3)*(NLS1*ALFA_21+NLS2*ALFA_32))*ALFA_43+
 (NLS4*((NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS4)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43))*ALFA_54+
 (NLS5*((NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS5)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54))*ALFA_65+
 (NLS6*((NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS6)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54+NLS5*ALFA_65))*ALFA_76);

PRINT WSLLS5;

WSLLS6=(NLS6*((NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS6)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54+NLS5*ALFA_65))*ALFA_76/

((NLS1*((NSLLS-NLS1)*ALFA_21+(NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76))*ALFA_21+
 (NLS2*((NSLLS-NLS2)*ALFA_32+(NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS
-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS2)*(NLS1*ALFA_21))*ALFA_32+
 (NLS3*((NSLLS-NLS3)*ALFA_43+(NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS
-NLS3)*(NLS1*ALFA_21+NLS2*ALFA_32))*ALFA_43+
 (NLS4*((NSLLS-NLS4)*ALFA_54+(NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS4)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43))*ALFA_54+
 (NLS5*((NSLLS-NLS5)*ALFA_65+(NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS5)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54))*ALFA_65+
 (NLS6*((NSLLS-NLS6)*ALFA_76)+(NSLLS-NLS6)*(NLS1*ALFA_21+NLS2*ALFA_32+NLS3*ALFA_43+NLS4*ALFA_54+NLS5*ALFA_65))*ALFA_76);


PRINT WSLLS6;

S_ANSLLS=WSLLS1+WSLLS2+WSLLS3+WSLLS4+WSLLS5+WSLLS6;

PRINT S_ANSLLS;

BETALSO=
(BETALS2*WSLLS1+BETALS3*WSLLS2+BETALS4*WSLLS3+BETALS5*WSLLS4+BETALS6*WSLLS5+BETALS7*WSLLS6);

PRINT BETALSO;


      */THE FOLLOWING LINES PROVIDES A CHECK THAT THE OLS-WEIGHTS ARE CORRECTLY COMPUTED/*;
      */IF THEY ARE: BETALSO=BOLS1LS(2,2) FOR THE ESTIMATES UNCORRECTED FOR CLASS.ERROR/*;

XHELPLS=AGE||AGEQ||SEXE;

THLS8_10=TH_SLLS[8:10,1];

SIMPSLLS=XOBS*ALFA;
INTSLLS=J(NSLLS,1,1);

XIMPSLLS=INTSLLS||SIMPSLLS;

BOLS1LS=INV(XIMPSLLS`*XIMPSLLS)*XIMPSLLS`*(LINC-XHELPLS*THLS8_10);

PRINT BOLS1LS;

 */THE FOLLOWING LINES CHECK THE DIFFERENCE BETWEEN THE WEIGHTING SCHEME AND
                              THE OLS ESTIMATOR FOR THE MULTIPLE REGRESSION/*;
 */THE FOLLOWING LINES CHECK THE DIFFERENCE BETWEEN THE WEIGHTING SCHEME AND
                              THE OLS ESTIMATOR FOR THE MULTIPLE REGRESSION/*;

XIMP2LS=INTSLLS||SIMPSLLS||AGE||AGEQ||SEXE;

BOLS2LS=INV(XIMP2LS`*XIMP2LS)*XIMP2LS`*LINC;

PRINT BOLS2LS;

RELDIFLS=((BOLS2LS[2,1]-BETALSO)/BOLS2LS[2,1])*100;

PRINT RELDIFLS;

*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BETALSO/*;
*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BETALSO/*;
*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BETALSO/*;


                    */FIRST THE DERIVATIVES OF BETASTWO WITH RESPECT TO THi_jTW/*;
                    */FIRST THE DERIVATIVES OF BETASTWO WITH RESPECT TO THi_jTW/*;
                    */FIRST THE DERIVATIVES OF BETASTWO WITH RESPECT TO THi_jTW/*;


DTHBLSO=(WSLLS1/ALFA_21)||(WSLLS2/ALFA_32)||(WSLLS3/ALFA_43)||
(WSLLS4/ALFA_54)||(WSLLS5/ALFA_65)||(WSLLS6/ALFA_76);

PRINT DTHBLSO;

                    */SECOND THE DERIVATIVE OF BETALSO WITH RESPECT TO ALFA_ij/*;
                    */SECOND THE DERIVATIVE OF BETALSO WITH RESPECT TO ALFA_ij/*;
                    */SECOND THE DERIVATIVE OF BETALSO WITH RESPECT TO ALFA_ij/*;

                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;
                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;
                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;

DABLSO=(WSLLS1*THLS2_1/(ALFA_21**2))||(WSLLS2*THLS3_2/(ALFA_32**2))||
(WSLLS3*THLS4_3/(ALFA_43**2))||(WSLLS4*THLS5_4/(ALFA_54**2))||
(WSLLS5*THLS6_5/(ALFA_65**2))||(WSLLS6*THLS7_6/(ALFA_76**2));

PRINT DABLSO;

                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BETALSO/*;
                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BETALSO/*;
                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BETALSO/*;


VBSLSO=(DTHBLSO*VDTHLS*DTHBLSO`)+(DABLSO*VALFA_*DABLSO`);

               */FOURTH THE CORRESPONDING STANDARD ERROR/*;
               */FOURTH THE CORRESPONDING STANDARD ERROR/*;
               */FOURTH THE CORRESPONDING STANDARD ERROR/*;

SBSLSO=SQRT(VBSLSO);
PRINT SBSLSO;

*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;
*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;
*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;

            */THE CROSS-SECTIONAL EQUATION/*;
            */THE CROSS-SECTIONAL EQUATION/*;
            */THE CROSS-SECTIONAL EQUATION/*;

USE J VAR{EDU1};READ ALL INTO EDU1;
USE J VAR{EDU2};READ ALL INTO EDU2;
USE J VAR{EDU3};READ ALL INTO EDU3;
USE J VAR{EDU4};READ ALL INTO EDU4;
USE J VAR{EDU5};READ ALL INTO EDU5;
USE J VAR{EDU6};READ ALL INTO EDU6;
USE J VAR{EDU7};READ ALL INTO EDU7;
USE J VAR{LAINK};READ ALL INTO LAINK;
USE J VAR{AGE};READ ALL INTO AGE;
USE J VAR{AGEQ};READ ALL INTO AGEQ;
USE J VAR{SEXE};READ ALL INTO SEXE;

NTW=NROW(LAINK);
INTTW=j(NTW,1,1);

                 */EARNINGS PREMIUMS/*;
                 */EARNINGS PREMIUMS/*;
                 */EARNINGS PREMIUMS/*;


XOBSTW=EDU1||EDU2||EDU3||EDU4||EDU5||EDU6||EDU7;

KTW=NCOL(XOBSTW);

PRINT NTW;

NTW1=SUM(EDU1);
NTW2=SUM(EDU2);
NTW3=SUM(EDU3);
NTW4=SUM(EDU4);
NTW5=SUM(EDU5);
NTW6=SUM(EDU6);
NTW7=SUM(EDU7);

PRINT NTW1;
PRINT NTW2;
PRINT NTW3;
PRINT NTW4;
PRINT NTW5;
PRINT NTW6;
PRINT NTW7;

*/CORRECTION MATRICES/*;

DBARTW1=SUM(EDU1)/NTW;
DBARTW2=SUM(EDU2)/NTW;
DBARTW3=SUM(EDU3)/NTW;
DBARTW4=SUM(EDU4)/NTW;
DBARTW5=SUM(EDU5)/NTW;
DBARTW6=SUM(EDU6)/NTW;
DBARTW7=SUM(EDU7)/NTW;

ABARTW=DBARTW1||DBARTW2||DBARTW3||DBARTW4||DBARTW5||DBARTW6||DBARTW7;
PRINT ABARTW;

  */A CONTROL THAT THE AVERAGES FOR EDUCATIONAL LEVEL SUM TO ONE/*;
  */A CONTROL THAT THE AVERAGES FOR EDUCATIONAL LEVEL SUM TO ONE/*;
  */A CONTROL THAT THE AVERAGES FOR EDUCATIONAL LEVEL SUM TO ONE/*;

SDBARTW=DBARTW1+DBARTW2+DBARTW3+DBARTW4+DBARTW5+DBARTW6+DBARTW7;
PRINT SDBARTW;

XTTW=INV(PT)*XOBSTW`;

    */CREATE MJUHAT OF FULLER/*;
    */CREATE MJUHAT OF FULLER/*;
    */CREATE MJUHAT OF FULLER/*;

MJUHATTW=INV(PT)*ABARTW`;

ABARTWT=ABARTW`;

PRINT MJUHATTW;

PRINT ABARTWT;

PRINT NTW;

*/CORRECTION MATRICES/*;

DB1TW=SUM(EDU1)/NTW;
DB2TW=SUM(EDU2)/NTW;
DB3TW=SUM(EDU3)/NTW;
DB4TW=SUM(EDU4)/NTW;
DB5TW=SUM(EDU5)/NTW;
DB6TW=SUM(EDU6)/NTW;
DB7TW=SUM(EDU7)/NTW;

ABTW=DB1TW||DB2TW||DB3TW||DB4TW||DB5TW||DB6TW||DB7TW;
PRINT ABTW;

SDBTW=DB1TW+DB2TW+DB3TW+DB4TW+DB5TW+DB6TW+DB7TW;
PRINT SDBTW;

          */INCLUDE AGE AGE-SQUARE AND SEX AS CONTROLS/*;
          */INCLUDE AGE AGE-SQUARE AND SEX AS CONTROLS/*;
          */INCLUDE AGE AGE-SQUARE AND SEX AS CONTROLS/*;

BIGXTTW=XTTW`||AGE||AGEQ||SEXE;

           */CREATE THE VARIANCE-COVARIANCE MATRIX FOR THE MEASUREMENT ERRORS/*;
           */CREATE THE VARIANCE-COVARIANCE MATRIX FOR THE MEASUREMENT ERRORS/*;
           */CREATE THE VARIANCE-COVARIANCE MATRIX FOR THE MEASUREMENT ERRORS/*;

ZERO1=J(7,3,0);
ZERO2=J(3,10,0);

SIGu11a=(MJUHATTW[1,1]/DB1TW)*INV(PT)*OMEG11*INV(PT)`;
SIGu22a=(MJUHATTW[2,1]/DB2TW)*INV(PT)*OMEG22*INV(PT)`;
SIGu33a=(MJUHATTW[3,1]/DB3TW)*INV(PT)*OMEG33*INV(PT)`;
SIGu44a=(MJUHATTW[4,1]/DB4TW)*INV(PT)*OMEG44*INV(PT)`;
SIGu55a=(MJUHATTW[5,1]/DB5TW)*INV(PT)*OMEG55*INV(PT)`;
SIGu66a=(MJUHATTW[6,1]/DB6TW)*INV(PT)*OMEG66*INV(PT)`;
SIGu77a=(MJUHATTW[7,1]/DB7TW)*INV(PT)*OMEG77*INV(PT)`;

SIGu_11=SIGu11a||ZERO1;
SIGu11TW=SIGu_11//ZERO2;

SIGu_22=SIGu22a||ZERO1;
SIGu22TW=SIGu_22//ZERO2;

SIGu_33=SIGu33a||ZERO1;
SIGu33TW=SIGu_33//ZERO2;

SIGu_44=SIGu44a||ZERO1;
SIGu44TW=SIGu_44//ZERO2;

SIGu_55=SIGu55a||ZERO1;
SIGu55TW=SIGu_55//ZERO2;

SIGu_66=SIGu66a||ZERO1;
SIGu66TW=SIGu_66//ZERO2;

SIGu_77=SIGu77a||ZERO1;
SIGu77TW=SIGu_77//ZERO2;

THETA=INV(BIGXTTW`*BIGXTTW-
NTW1*SIGu11TW-NTW2*SIGu22TW-NTW3*SIGu33TW-NTW4*SIGu44TW-
NTW5*SIGu55TW-NTW6*SIGu66TW-NTW7*SIGu77TW)*BIGXTTW`*LAINK;

PRINT THETA;

THETA=INV(BIGXTTW`*BIGXTTW-
NTW1*SIGu11TW-NTW2*SIGu22TW-NTW3*SIGu33TW-NTW4*SIGu44TW-
NTW5*SIGu55TW-NTW6*SIGu66TW-NTW7*SIGu77TW)*BIGXTTW`*LAINK;

PRINT THETA;

          */A TEST TO SEE THAT THE ADJUSTED "X`*X" MATRIX IS OK/*;

TEST2_1=VECDIAG((BIGXTTW`*BIGXTTW-NTW1*SIGu11TW-NTW2*SIGu22TW-NTW3*SIGu33TW-NTW4*SIGu44TW-
NTW5*SIGu55TW-NTW6*SIGu66TW-NTW7*SIGu77TW));
TEST2=TEST2_1[1:7,1];
PRINT TEST2;

MJUHTWN=NTW*MJUHATTW;
PRINT MJUHTWN;

ISOK2=TEST2-MJUHTWN;
PRINT ISOK2;

*/BESIDE ROUNDING ERRORS IN THE COMPUTATION OF THE INV(MATRIX): TEST2=MJUHTWN IF ADJUSTMENT OK/;

        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;
        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;
        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;

VHATTW=LAINK-BIGXTTW*THETA;

VHBIGTW=VHATTW||VHATTW||VHATTW||VHATTW||VHATTW||VHATTW||VHATTW||VHATTW||VHATTW||VHATTW;

XVHATTW=BIGXTTW#VHBIGTW;

THETA_=THETA[1:7,1];

PRINT THETA_;

SIGUUTW=SIGu11TW*(-1)*THETA||SIGu22TW*(-1)*THETA||SIGu33TW*(-1)*THETA||SIGu44TW*(-1)*THETA||
SIGu55TW*(-1)*THETA||SIGu66TW*(-1)*THETA||SIGu77TW*(-1)*THETA;

PRINT SIGUUTW;

PICKTW=SIGUUTW*XOBSTW`;

DHATTTW=XVHATTW`-PICKTW;

GHATTW=(1/(NTW-KTW))*DHATTTW*DHATTTW`;

PRINT GHATTW;

VTH=(1/NTW)*
INV((1/NTW)*(BIGXTTW`*BIGXTTW-
NTW1*SIGu11TW-NTW2*SIGu22TW-NTW3*SIGu33TW-NTW4*SIGu44TW-
NTW5*SIGu55TW-NTW6*SIGu66TW-NTW7*SIGu77TW))*
GHATTW*
INV((1/NTW)*(BIGXTTW`*BIGXTTW-
NTW1*SIGu11TW-NTW2*SIGu22TW-NTW3*SIGu33TW-NTW4*SIGu44TW-
NTW5*SIGu55TW-NTW6*SIGu66TW-NTW7*SIGu77TW));

PRINT VTH;

            */THE STANDARD ERRORS OF EACH ELEMENT IN THETA/*;
            */THE STANDARD ERRORS OF EACH ELEMENT IN THETA/*;
            */THE STANDARD ERRORS OF EACH ELEMENT IN THETA/*;

SETH=SQRT(VECDIAG(VTH));
PRINT SETH;

        */NOW START TO CONSTRUCT WAGE PREMIUMS RELATIVE TO THE LOWEST EDUCATIONAL LEVELS/*;
        */NOW START TO CONSTRUCT WAGE PREMIUMS RELATIVE TO THE LOWEST EDUCATIONAL LEVELS/*;
        */NOW START TO CONSTRUCT WAGE PREMIUMS RELATIVE TO THE LOWEST EDUCATIONAL LEVELS/*;

THETA1TW=THETA[1,1];
THETA2TW=THETA[2,1];
THETA3TW=THETA[3,1];
THETA4TW=THETA[4,1];
THETA5TW=THETA[5,1];
THETA6TW=THETA[6,1];
THETA7TW=THETA[7,1];


            */THE WAGE PREMIUMS RELATIVE TO CATEGORY 1/*;
            */THE WAGE PREMIUMS RELATIVE TO CATEGORY 1/*;
            */THE WAGE PREMIUMS RELATIVE TO CATEGORY 1/*;


WP21=THETA2TW-THETA1TW;
WP31=THETA3TW-THETA1TW;
WP41=THETA4TW-THETA1TW;
WP51=THETA5TW-THETA1TW;
WP61=THETA6TW-THETA1TW;
WP71=THETA7TW-THETA1TW;

WP=WP21//WP31//WP41//WP51//WP61//WP71;

PRINT WP;

     */CONSTRUCT THE VARIANCE OF EACH WPi/*;
     */CONSTRUCT THE VARIANCE OF EACH WPi/*;
     */CONSTRUCT THE VARIANCE OF EACH WPi/*;

VWP21=VTH[2,2]+VTH[1,1]-2*VTH[2,1];
VWP31=VTH[3,3]+VTH[1,1]-2*VTH[3,1];
VWP41=VTH[4,4]+VTH[1,1]-2*VTH[4,1];
VWP51=VTH[5,5]+VTH[1,1]-2*VTH[5,1];
VWP61=VTH[6,6]+VTH[1,1]-2*VTH[6,1];
VWP71=VTH[7,7]+VTH[1,1]-2*VTH[7,1];

    */THE CORRESPONDING STANDARD ERRORS/*;
    */THE CORRESPONDING STANDARD ERRORS/*;
    */THE CORRESPONDING STANDARD ERRORS/*;

SEWP=
SQRT(VWP21)//SQRT(VWP31)//SQRT(VWP41)//SQRT(VWP51)//SQRT(VWP61)//SQRT(VWP71);
PRINT SEWP;

    */ESTIMATE THE WAGE PREMIUMS RELATIVE TO THE CLOSEST LOWER CATEGORY/*;
    */ESTIMATE THE WAGE PREMIUMS RELATIVE TO THE CLOSEST LOWER CATEGORY/*;
    */ESTIMATE THE WAGE PREMIUMS RELATIVE TO THE CLOSEST LOWER CATEGORY/*;

TH2_1TW=THETA2TW-THETA1TW;
TH3_2TW=THETA3TW-THETA2TW;
TH4_3TW=THETA4TW-THETA3TW;
TH5_4TW=THETA5TW-THETA4TW;
TH6_5TW=THETA6TW-THETA5TW;
TH7_6TW=THETA7TW-THETA6TW;

TH_TW=TH2_1TW||TH3_2TW||TH4_3TW||TH5_4TW||TH6_5TW||TH7_6TW;

PRINT TH_TW;

        */CONSTRUCT THE VARIANCE MATRIX OF TH_TW/*;
        */CONSTRUCT THE VARIANCE MATRIX OF TH_TW/*;
        */CONSTRUCT THE VARIANCE MATRIX OF TH_TW/*;

     */FIRST CONSTRUCT THE VARIANCE OF EACH THi_i1/*;
     */FIRST CONSTRUCT THE VARIANCE OF EACH THi_i1/*;
     */FIRST CONSTRUCT THE VARIANCE OF EACH THi_i1/*;

VTH2_1TW=VTH[2,2]+VTH[1,1]-2*VTH[2,1];
VTH3_2TW=VTH[3,3]+VTH[2,2]-2*VTH[3,2];
VTH4_3TW=VTH[4,4]+VTH[3,3]-2*VTH[4,3];
VTH5_4TW=VTH[5,5]+VTH[4,4]-2*VTH[5,4];
VTH6_5TW=VTH[6,6]+VTH[5,5]-2*VTH[6,5];
VTH7_6TW=VTH[7,7]+VTH[6,6]-2*VTH[7,6];

    */SECOND CONSTRUCT THE COVARIANCES THi_ij,THj_ji/*;
    */SECOND CONSTRUCT THE COVARIANCES THi_ij,THj_ji/*;
    */SECOND CONSTRUCT THE COVARIANCES THi_ij,THj_ji/*;

CTH2132=VTH[2,3]-VTH[2,2]-VTH[1,3]+VTH[1,2];
CTH2143=VTH[2,4]-VTH[2,3]-VTH[1,4]+VTH[1,3];
CTH2154=VTH[2,5]-VTH[2,4]-VTH[1,5]+VTH[1,4];
CTH2165=VTH[2,6]-VTH[2,5]-VTH[1,6]+VTH[1,5];
CTH2176=VTH[2,7]-VTH[2,6]-VTH[1,7]+VTH[1,6];

CTH3221=VTH[3,2]-VTH[3,1]-VTH[2,2]+VTH[2,1];
CTH3243=VTH[3,4]-VTH[3,3]-VTH[2,4]+VTH[2,3];
CTH3254=VTH[3,5]-VTH[3,4]-VTH[2,5]+VTH[2,4];
CTH3265=VTH[3,6]-VTH[3,5]-VTH[2,6]+VTH[2,5];
CTH3276=VTH[3,7]-VTH[3,6]-VTH[2,7]+VTH[2,6];

CTH4321=VTH[4,2]-VTH[4,1]-VTH[3,2]+VTH[3,1];
CTH4332=VTH[4,3]-VTH[4,2]-VTH[3,3]+VTH[3,2];
CTH4354=VTH[4,5]-VTH[4,4]-VTH[3,5]+VTH[3,4];
CTH4365=VTH[4,6]-VTH[4,5]-VTH[3,6]+VTH[3,5];
CTH4376=VTH[4,7]-VTH[4,6]-VTH[3,7]+VTH[3,6];

CTH5421=VTH[5,2]-VTH[5,1]-VTH[4,2]+VTH[4,1];
CTH5432=VTH[5,3]-VTH[5,2]-VTH[4,3]+VTH[4,2];
CTH5443=VTH[5,4]-VTH[5,3]-VTH[4,4]+VTH[4,3];
CTH5465=VTH[5,6]-VTH[5,5]-VTH[4,6]+VTH[4,5];
CTH5476=VTH[5,7]-VTH[5,6]-VTH[4,7]+VTH[4,6];

CTH6521=VTH[6,2]-VTH[6,1]-VTH[5,2]+VTH[5,1];
CTH6532=VTH[6,3]-VTH[6,2]-VTH[5,3]+VTH[5,2];
CTH6543=VTH[6,4]-VTH[6,3]-VTH[5,4]+VTH[5,3];
CTH6554=VTH[6,5]-VTH[6,4]-VTH[5,5]+VTH[5,4];
CTH6576=VTH[6,7]-VTH[6,6]-VTH[5,7]+VTH[5,6];

CTH7621=VTH[7,2]-VTH[7,1]-VTH[6,2]+VTH[6,1];
CTH7632=VTH[7,3]-VTH[7,2]-VTH[6,3]+VTH[6,2];
CTH7643=VTH[7,4]-VTH[7,3]-VTH[6,4]+VTH[6,3];
CTH7654=VTH[7,5]-VTH[7,4]-VTH[6,5]+VTH[6,4];
CTH7665=VTH[7,6]-VTH[7,5]-VTH[6,6]+VTH[6,5];

          */THE ROWS OF THE MATRIX/*;
          */THE ROWS OF THE MATRIX/*;
          */THE ROWS OF THE MATRIX/*;

VTH_R1=VTH2_1TW||CTH2132||CTH2143||CTH2154||CTH2165||CTH2176;
VTH_R2=CTH3221||VTH3_2TW||CTH3243||CTH3254||CTH3265||CTH3276;
VTH_R3=CTH4321||CTH4332||VTH4_3TW||CTH4354||CTH4365||CTH4376;
VTH_R4=CTH5421||CTH5432||CTH5443||VTH5_4TW||CTH5465||CTH5476;
VTH_R5=CTH6521||CTH6532||CTH6543||CTH6554||VTH6_5TW||CTH6576;
VTH_R6=CTH7621||CTH7632||CTH7643||CTH7654||CTH7665||VTH7_6TW;

            */THE COMPLETE MATRIX/*;
            */THE COMPLETE MATRIX/*;
            */THE COMPLETE MATRIX/*;


VTH_=VTH_R1//VTH_R2//VTH_R3//VTH_R4//VTH_R5//VTH_R6;
PRINT VTH_;

                  */THE STANDARD ERRORS/*;
                  */THE STANDARD ERRORS/*;
                  */THE STANDARD ERRORS/*;

SETH_=SQRT(VECDIAG(VTH_));
PRINT SETH_;

         */THE RETURNS TO ADDITIONAL YEARS OF SCHOOLING AT EACH LEVEL/*;
         */THE RETURNS TO ADDITIONAL YEARS OF SCHOOLING AT EACH LEVEL/*;
         */THE RETURNS TO ADDITIONAL YEARS OF SCHOOLING AT EACH LEVEL/*;

BETASTW2=TH2_1TW/ALFA_21;
BETASTW3=TH3_2TW/ALFA_32;
BETASTW4=TH4_3TW/ALFA_43;
BETASTW5=TH5_4TW/ALFA_54;
BETASTW6=TH6_5TW/ALFA_65;
BETASTW7=TH7_6TW/ALFA_76;

BETASTW=BETASTW2//BETASTW3//BETASTW4//BETASTW5//BETASTW6//BETASTW7;
PRINT BETASTW;

           */THE VARIANCE MATRIX OF EACH BETASTWi i = 2, 3, ..., 7/*;
           */THE VARIANCE MATRIX OF EACH BETASTWi i = 2, 3, ..., 7/*;
           */THE VARIANCE MATRIX OF EACH BETASTWi i = 2, 3, ..., 7/*;

PRINT VTH_;
PRINT VALFA_;

VBSTW2=(VTH_[1,1]/(ALFA_21**2))+((TH2_1TW**2)*VALFA_[1,1])/((ALFA_21**2)*(ALFA_21**2));
VBSTW3=(VTH_[2,2]/(ALFA_32**2))+((TH3_2TW**2)*VALFA_[2,2])/((ALFA_32**2)*(ALFA_32**2));
VBSTW4=(VTH_[3,3]/(ALFA_43**2))+((TH4_3TW**2)*VALFA_[3,3])/((ALFA_43**2)*(ALFA_43**2));
VBSTW5=(VTH_[4,4]/(ALFA_54**2))+((TH5_4TW**2)*VALFA_[4,4])/((ALFA_54**2)*(ALFA_54**2));
VBSTW6=(VTH_[5,5]/(ALFA_65**2))+((TH6_5TW**2)*VALFA_[5,5])/((ALFA_65**2)*(ALFA_65**2));
VBSTW7=(VTH_[6,6]/(ALFA_76**2))+((TH7_6TW**2)*VALFA_[6,6])/((ALFA_76**2)*(ALFA_76**2));

PRINT VBSTW2;
PRINT VBSTW3;
PRINT VBSTW4;
PRINT VBSTW5;
PRINT VBSTW6;
PRINT VBSTW7;

          */THE CORRESPONDING STANDARD ERRORS/*;
          */THE CORRESPONDING STANDARD ERRORS/*;
          */THE CORRESPONDING STANDARD ERRORS/*;

SBSTW=SQRT(VBSTW2)//SQRT(VBSTW3)//SQRT(VBSTW4)//SQRT(VBSTW5)//SQRT(VBSTW6)//SQRT(VBSTW7);
PRINT SBSTW;

  */ESTIMATE THE WAGE PREMIUMS RELATIVE TO "TRULY PRECEDING" LEVEL FOR LEVELS 4 AND 6/*;

TH4_2TW=THETA4TW-THETA2TW;
TH6_4TW=THETA6TW-THETA4TW;

ALFA_42=ALFA[4,1]-ALFA[2,1];
ALFA_64=ALFA[6,1]-ALFA[4,1];

BETATW42=TH4_2TW/ALFA_42;
BETATW64=TH6_4TW/ALFA_64;

PRINT BETATW42;
PRINT BETATW64;

*/THE CORRESPONDING STANDARD ERRORS/*;

VTH4_2TW=VTH[4,4]+VTH[2,2]-2*VTH[4,2];
VTH6_4TW=VTH[6,6]+VTH[4,4]-2*VTH[6,4];

VALFA_42=VALFA[4,4]+VALFA[2,2]-2*VALFA[4,2];
VALFA_64=VALFA[6,6]+VALFA[4,4]-2*VALFA[6,4];

VBSTW42=(VTH4_2TW/(ALFA_42**2))+((TH4_2TW**2)*VALFA_42)/((ALFA_42**2)*(ALFA_42**2));
VBSTW64=(VTH6_4TW/(ALFA_64**2))+((TH6_4TW**2)*VALFA_64)/((ALFA_64**2)*(ALFA_64**2));

SBSTW42=SQRT(VBSTW42);
SBSTW64=SQRT(VBSTW64);

PRINT SBSTW42;
PRINT SBSTW64;


    */WEIGH THE SEPARATE ESTIMATES TOGETHER WITH THE OLS WEIGHTING FUNCTION/*;
    */WEIGH THE SEPARATE ESTIMATES TOGETHER WITH THE OLS WEIGHTING FUNCTION/*;
    */WEIGH THE SEPARATE ESTIMATES TOGETHER WITH THE OLS WEIGHTING FUNCTION/*;


                                            */FIRST THE OLS-WEIGHTS/*;
                                            */FIRST THE OLS-WEIGHTS/*;
                                            */FIRST THE OLS-WEIGHTS/*;

PRINT MJUHATTW;

N1=NTW*(MJUHATTW[1,1]);
N2=NTW*(MJUHATTW[1,1]+MJUHATTW[2,1]);
N3=NTW*(MJUHATTW[1,1]+MJUHATTW[2,1]+MJUHATTW[3,1]);
N4=NTW*(MJUHATTW[1,1]+MJUHATTW[2,1]+MJUHATTW[3,1]+MJUHATTW[4,1]);
N5=NTW*(MJUHATTW[1,1]+MJUHATTW[2,1]+MJUHATTW[3,1]+MJUHATTW[4,1]+MJUHATTW[5,1]);
N6=NTW*(MJUHATTW[1,1]+MJUHATTW[2,1]+MJUHATTW[3,1]+MJUHATTW[4,1]+MJUHATTW[5,1]+MJUHATTW[6,1]);
N7=NTW*(MJUHATTW[1,1]+MJUHATTW[2,1]+MJUHATTW[3,1]+MJUHATTW[4,1]+MJUHATTW[5,1]+MJUHATTW[6,1]+
MJUHATTW[7,1]);

PRINT N1;
PRINT N2;
PRINT N3;
PRINT N4;
PRINT N5;
PRINT N6;
PRINT N7;
PRINT NTW;

W1=
(N1*((NTW-N1)*ALFA_21+(NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76))*ALFA_21/

((N1*((NTW-N1)*ALFA_21+(NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76))*ALFA_21+
 (N2*((NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N2)*(N1*ALFA_21))*ALFA_32+
 (N3*((NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N3)*(N1*ALFA_21+N2*ALFA_32))*ALFA_43+
 (N4*((NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N4)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43))*ALFA_54+
 (N5*((NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N5)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54))*ALFA_65+
 (N6*((NTW-N6)*ALFA_76)+(NTW-N6)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54+N5*ALFA_65))*ALFA_76);

PRINT W1;

W2=
(N2*((NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N2)*(N1*ALFA_21))*ALFA_32/

((N1*((NTW-N1)*ALFA_21+(NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76))*ALFA_21+
 (N2*((NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N2)*(N1*ALFA_21))*ALFA_32+
 (N3*((NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N3)*(N1*ALFA_21+N2*ALFA_32))*ALFA_43+
 (N4*((NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N4)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43))*ALFA_54+
 (N5*((NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N5)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54))*ALFA_65+
 (N6*((NTW-N6)*ALFA_76)+(NTW-N6)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54+N5*ALFA_65))*ALFA_76);


PRINT W2;

W3=(N3*((NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N3)*(N1*ALFA_21+N2*ALFA_32))*ALFA_43/

((N1*((NTW-N1)*ALFA_21+(NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76))*ALFA_21+
 (N2*((NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N2)*(N1*ALFA_21))*ALFA_32+
 (N3*((NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N3)*(N1*ALFA_21+N2*ALFA_32))*ALFA_43+
 (N4*((NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N4)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43))*ALFA_54+
 (N5*((NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N5)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54))*ALFA_65+
 (N6*((NTW-N6)*ALFA_76)+(NTW-N6)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54+N5*ALFA_65))*ALFA_76);


PRINT W3;

W4=(N4*((NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N4)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43))*ALFA_54/

((N1*((NTW-N1)*ALFA_21+(NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76))*ALFA_21+
 (N2*((NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N2)*(N1*ALFA_21))*ALFA_32+
 (N3*((NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N3)*(N1*ALFA_21+N2*ALFA_32))*ALFA_43+
 (N4*((NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N4)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43))*ALFA_54+
 (N5*((NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N5)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54))*ALFA_65+
 (N6*((NTW-N6)*ALFA_76)+(NTW-N6)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54+N5*ALFA_65))*ALFA_76);


PRINT W4;

W5=(N5*((NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N5)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54))*ALFA_65/

((N1*((NTW-N1)*ALFA_21+(NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76))*ALFA_21+
 (N2*((NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N2)*(N1*ALFA_21))*ALFA_32+
 (N3*((NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N3)*(N1*ALFA_21+N2*ALFA_32))*ALFA_43+
 (N4*((NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N4)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43))*ALFA_54+
 (N5*((NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N5)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54))*ALFA_65+
 (N6*((NTW-N6)*ALFA_76)+(NTW-N6)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54+N5*ALFA_65))*ALFA_76);


PRINT W5;

W6=(N6*((NTW-N6)*ALFA_76)+(NTW-N6)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54+N5*ALFA_65))*ALFA_76/


((N1*((NTW-N1)*ALFA_21+(NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76))*ALFA_21+
 (N2*((NTW-N2)*ALFA_32+(NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N2)*(N1*ALFA_21))*ALFA_32+
 (N3*((NTW-N3)*ALFA_43+(NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N3)*(N1*ALFA_21+N2*ALFA_32))*ALFA_43+
 (N4*((NTW-N4)*ALFA_54+(NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N4)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43))*ALFA_54+
 (N5*((NTW-N5)*ALFA_65+(NTW-N6)*ALFA_76)+(NTW-N5)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54))*ALFA_65+
 (N6*((NTW-N6)*ALFA_76)+(NTW-N6)*(N1*ALFA_21+N2*ALFA_32+N3*ALFA_43+N4*ALFA_54+N5*ALFA_65))*ALFA_76);


PRINT W6;

SUMMAN=W1+W2+W3+W4+W5+W6;

PRINT SUMMAN;

BETASTWO=
(BETASTW2*W1+BETASTW3*W2+BETASTW4*W3+BETASTW5*W4+BETASTW6*W5+BETASTW7*W6);

PRINT BETASTWO;


      */THE FOLLOWING LINES PROVIDES A CHECK THAT THE OLS-WEIGHTS ARE CORRECTLY COMPUTED/*;
      */IF THEY ARE: BETASTWO=BIMPOLS1(2,2) FOR THE ESTIMATES UNCORRECTED FOR CLASS.ERROR/*;

XHELP=AGE||AGEQ||SEXE;

THETA__=THETA[8:10,1];

SIMP=XOBSTW*ALFA;

XIMP1=INTTW||SIMP;

BIMPOLS1=INV(XIMP1`*XIMP1)*XIMP1`*(LAINK-XHELP*THETA__);

PRINT BIMPOLS1; */BIMPOLS1=BETASTWO UNDER THE ASSUMPTION OF NO ERROR IN EDUCATIONAL LEVELS/*;

 */THE FOLLOWING LINES CHECKS THE DIFFERENCE BETWEEN THE WEIGHTING SCHEME AND
                              THE OLS ESTIMATOR FOR THE MULTIPLE REGRESSION/*;
 */THE FOLLOWING LINES CHECKS THE DIFFERENCE BETWEEN THE WEIGHTING SCHEME AND
                              THE OLS ESTIMATOR FOR THE MULTIPLE REGRESSION/*;

XIMP2=INTTW||SIMP||AGE||AGEQ||SEXE;

BIMPOLS2=INV(XIMP2`*XIMP2)*XIMP2`*LAINK;

PRINT BIMPOLS2;

RESIMP2=LAINK-XIMP2*BIMPOLS2;

RESIMP2Q=INV(NTW)*RESIMP2`*RESIMP2;

VBIMOLS2=RESIMP2Q*INV(XIMP2`*XIMP2);

VBIMPS2=VBIMOLS2[2,2];

SBIMPS2=SQRT(VBIMPS2);

PRINT SBIMPS2;

RELDIFTW=((BIMPOLS2[2,1]-BETASTWO)/BIMPOLS2[2,1])*100;

*/RELDIF=PERCENTAGE DIFFERENCE BETWEEN WEIGHTING SCHEME AND THE OLS ESTIMATOR ASSUMING NO ERROR/*;
*/RELDIF=PERCENTAGE DIFFERENCE BETWEEN WEIGHTING SCHEME AND THE OLS ESTIMATOR ASSUMING NO ERROR/*;
*/RELDIF=PERCENTAGE DIFFERENCE BETWEEN WEIGHTING SCHEME AND THE OLS ESTIMATOR ASSUMING NO ERROR/*;

PRINT RELDIFTW;

TH_TW=TH2_1TW||TH3_2TW||TH4_3TW||TH5_4TW||TH6_5TW||TH7_6TW;

PRINT TH_TW;


*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BETASTWO/*;
*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BETASTWO/*;
*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BETASTWO/*;


                    */FIRST THE DERIVATIVES OF BETASTWO WITH RESPECT TO THi_jTW/*;
                    */FIRST THE DERIVATIVES OF BETASTWO WITH RESPECT TO THi_jTW/*;
                    */FIRST THE DERIVATIVES OF BETASTWO WITH RESPECT TO THi_jTW/*;


DTHBTWO=(W1/ALFA_21)||(W2/ALFA_32)||(W3/ALFA_43)||
(W4/ALFA_54)||(W5/ALFA_65)||(W6/ALFA_76);

PRINT DTHBTWO;

                    */SECOND THE DERIVATIVE OF BETASTO WITH RESPECT TO ALFA_ij/*;
                    */SECOND THE DERIVATIVE OF BETASTO WITH RESPECT TO ALFA_ij/*;
                    */SECOND THE DERIVATIVE OF BETASTO WITH RESPECT TO ALFA_ij/*;

                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;
                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;
                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;

DABTWO=(W1*TH2_1TW/(ALFA_21**2))||(W2*TH3_2TW/(ALFA_32**2))||
(W3*TH4_3TW/(ALFA_43**2))||(W4*TH5_4TW/(ALFA_54**2))||
(W5*TH6_5TW/(ALFA_65**2))||(W6*TH7_6TW/(ALFA_76**2));

PRINT DABTWO;

                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BETASTWO/*;
                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BETASTWO/*;
                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BETASTWO/*;


VBSTWO=(DTHBTWO*VTH_*DTHBTWO`)+(DABTWO*VALFA_*DABTWO`);

               */FOURTH THE CORRESPONDING STANDARD ERROR/*;
               */FOURTH THE CORRESPONDING STANDARD ERROR/*;
               */FOURTH THE CORRESPONDING STANDARD ERROR/*;

SBSTWO=SQRT(VBSTWO);
PRINT SBSTWO;

                 */THE WITHIN-PAIR EQUATION/*;
                 */THE WITHIN-PAIR EQUATION/*;
                 */THE WITHIN-PAIR EQUATION/*;

USE GBASE2 VAR{DLAINK};READ ALL INTO DY;
USE GBASE2 VAR{DEDU1};READ ALL INTO DEDU1;
USE GBASE2 VAR{DEDU2};READ ALL INTO DEDU2;
USE GBASE2 VAR{DEDU3};READ ALL INTO DEDU3;
USE GBASE2 VAR{DEDU4};READ ALL INTO DEDU4;
USE GBASE2 VAR{DEDU5};READ ALL INTO DEDU5;
USE GBASE2 VAR{DEDU6};READ ALL INTO DEDU6;
USE GBASE2 VAR{DEDU7};READ ALL INTO DEDU7;
USE GBASE2 VAR{EDU11};READ ALL INTO EDU11;
USE GBASE2 VAR{EDU21};READ ALL INTO EDU21;
USE GBASE2 VAR{EDU31};READ ALL INTO EDU31;
USE GBASE2 VAR{EDU41};READ ALL INTO EDU41;
USE GBASE2 VAR{EDU51};READ ALL INTO EDU51;
USE GBASE2 VAR{EDU61};READ ALL INTO EDU61;
USE GBASE2 VAR{EDU71};READ ALL INTO EDU71;
USE GBASE2 VAR{EDU12};READ ALL INTO EDU12;
USE GBASE2 VAR{EDU22};READ ALL INTO EDU22;
USE GBASE2 VAR{EDU32};READ ALL INTO EDU32;
USE GBASE2 VAR{EDU42};READ ALL INTO EDU42;
USE GBASE2 VAR{EDU52};READ ALL INTO EDU52;
USE GBASE2 VAR{EDU62};READ ALL INTO EDU62;
USE GBASE2 VAR{EDU72};READ ALL INTO EDU72;

NTWPAIR=NROW(DY);

PRINT NTWPAIR;


            */NOW START THE FULLER ESTIMATOR/*;
            */NOW START THE FULLER ESTIMATOR/*;
            */NOW START THE FULLER ESTIMATOR/*;


XOBSTW1=EDU11||EDU21||EDU31||EDU41||EDU51||EDU61||EDU71;
XOBSTW2=EDU12||EDU22||EDU32||EDU42||EDU52||EDU62||EDU72;

DXOBSTW=XOBSTW1-XOBSTW2;

NTW11=SUM(EDU11);
NTW21=SUM(EDU21);
NTW31=SUM(EDU31);
NTW41=SUM(EDU41);
NTW51=SUM(EDU51);
NTW61=SUM(EDU61);
NTW71=SUM(EDU71);

NTW12=SUM(EDU12);
NTW22=SUM(EDU22);
NTW32=SUM(EDU32);
NTW42=SUM(EDU42);
NTW52=SUM(EDU52);
NTW62=SUM(EDU62);
NTW72=SUM(EDU72);

*/CORRECTION MATRICES/*;

DBARTW11=SUM(EDU11)/(NTWPAIR);
DBARTW21=SUM(EDU21)/(NTWPAIR);
DBARTW31=SUM(EDU31)/(NTWPAIR);
DBARTW41=SUM(EDU41)/(NTWPAIR);
DBARTW51=SUM(EDU51)/(NTWPAIR);
DBARTW61=SUM(EDU61)/(NTWPAIR);
DBARTW71=SUM(EDU71)/(NTWPAIR);

DBARTW12=SUM(EDU12)/(NTWPAIR);
DBARTW22=SUM(EDU22)/(NTWPAIR);
DBARTW32=SUM(EDU32)/(NTWPAIR);
DBARTW42=SUM(EDU42)/(NTWPAIR);
DBARTW52=SUM(EDU52)/(NTWPAIR);
DBARTW62=SUM(EDU62)/(NTWPAIR);
DBARTW72=SUM(EDU72)/(NTWPAIR);

ABARTW1=DBARTW11||DBARTW21||DBARTW31||DBARTW41||DBARTW51||DBARTW61||DBARTW71;
PRINT ABARTW1;

ABARTW2=DBARTW12||DBARTW22||DBARTW32||DBARTW42||DBARTW52||DBARTW62||DBARTW72;
PRINT ABARTW2;

XTTW1=INV(PT)*XOBSTW1`;
XTTW2=INV(PT)*XOBSTW2`;

    */CREATE MJUHAT OF FULLER/*;
    */CREATE MJUHAT OF FULLER/*;
    */CREATE MJUHAT OF FULLER/*;

MJUHATW1=INV(PT)*ABARTW1`;
MJUHATW2=INV(PT)*ABARTW2`;

ABARTWT1=ABARTW1`;
ABARTWT2=ABARTW2`;

PRINT MJUHATW1;
PRINT MJUHATW2;
PRINT ABARTWT1;
PRINT ABARTWT2;

*/CORRECTION MATRICES/*;

DB1TW1=SUM(EDU11)/(NTWPAIR);
DB2TW1=SUM(EDU21)/(NTWPAIR);
DB3TW1=SUM(EDU31)/(NTWPAIR);
DB4TW1=SUM(EDU41)/(NTWPAIR);
DB5TW1=SUM(EDU51)/(NTWPAIR);
DB6TW1=SUM(EDU61)/(NTWPAIR);
DB7TW1=SUM(EDU71)/(NTWPAIR);

DB1TW2=SUM(EDU12)/(NTWPAIR);
DB2TW2=SUM(EDU22)/(NTWPAIR);
DB3TW2=SUM(EDU32)/(NTWPAIR);
DB4TW2=SUM(EDU42)/(NTWPAIR);
DB5TW2=SUM(EDU52)/(NTWPAIR);
DB6TW2=SUM(EDU62)/(NTWPAIR);
DB7TW2=SUM(EDU72)/(NTWPAIR);

ABTW1=DB1TW1||DB2TW1||DB3TW1||DB4TW1||DB5TW1||DB6TW1||DB7TW1;
PRINT ABTW1;

ABTW2=DB1TW2||DB2TW2||DB3TW2||DB4TW2||DB5TW2||DB6TW2||DB7TW2;
PRINT ABTW2;

DXTTW=XTTW1-XTTW2;

DX=(DXTTW*DXTTW`);
DX_1=DX[2:7,2:7];

DXTTW_1=DXTTW[2:7,1:NTWPAIR];

SU11=SIGu11a[2:7,2:7];
SU22=SIGu22a[2:7,2:7];
SU33=SIGu33a[2:7,2:7];
SU44=SIGu44a[2:7,2:7];
SU55=SIGu55a[2:7,2:7];
SU66=SIGu66a[2:7,2:7];
SU77=SIGu77a[2:7,2:7];

TWINP=INV(DX_1-
(NTW11+NTW12)*SU11-(NTW21+NTW22)*SU22-(NTW31+NTW32)*SU33-(NTW41+NTW42)*SU44-
(NTW51+NTW52)*SU55-(NTW61+NTW62)*SU66-(NTW71+NTW72)*SU77)*DXTTW_1*DY;

PRINT TWINP;

          */A TEST TO SEE THAT THE ADJUSTED "X`*X" MATRIX IS OK/*;

F=XOBSTW1`*XOBSTW2;
FSTAR=INV(R`)*F*INV(R);
PRINT F;
PRINT FSTAR;

TEST3=VECDIAG((DX_1-(NTW11+NTW12)*SU11-(NTW21+NTW22)*SU22-(NTW31+NTW32)*SU33-(NTW41+NTW42)*SU44-
(NTW51+NTW52)*SU55-(NTW61+NTW62)*SU66-(NTW71+NTW72)*SU77));

TEST4_2=SUM(FSTAR[2,1:7])+SUM(FSTAR[1:7,2])-2*FSTAR[2,2];
TEST4_3=SUM(FSTAR[3,1:7])+SUM(FSTAR[1:7,3])-2*FSTAR[3,3];
TEST4_4=SUM(FSTAR[4,1:7])+SUM(FSTAR[1:7,4])-2*FSTAR[4,4];
TEST4_5=SUM(FSTAR[5,1:7])+SUM(FSTAR[1:7,5])-2*FSTAR[5,5];
TEST4_6=SUM(FSTAR[6,1:7])+SUM(FSTAR[1:7,6])-2*FSTAR[6,6];
TEST4_7=SUM(FSTAR[7,1:7])+SUM(FSTAR[1:7,7])-2*FSTAR[7,7];
TEST4=TEST4_2//TEST4_3//TEST4_4//TEST4_5//TEST4_6//TEST4_7;

PRINT TEST3;
PRINT TEST4;

ISOK3=TEST3-TEST4;
PRINT ISOK3;

*/BESIDE ROUNDING ERRORS IN THE COMPUTATION OF THE INV(MATRIX): TEST3=TEST4 IF ADJUSTMENT OK/;

        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;
        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;
        */NOW TURN TO THE VARIANCE-COVARIANCE MATRIX OF BY. CALL THIS MATRIX "VBBYTW"/*;

VHATTW=DY-DXTTW_1`*TWINP;

VHBIGTW=VHATTW||VHATTW||VHATTW||VHATTW||VHATTW||VHATTW;

XVHATTW=DXTTW_1`#VHBIGTW;

SIGUUTW=SU11*(-1)*TWINP||SU22*(-1)*TWINP||SU33*(-1)*TWINP||SU44*(-1)*TWINP||
SU55*(-1)*TWINP||SU66*(-1)*TWINP||SU77*(-1)*TWINP;

PRINT SIGUUTW;

PXOBSTW=XOBSTW1+XOBSTW2;

PICKTW=SIGUUTW*PXOBSTW`;

DHATTTW=XVHATTW`-PICKTW;

GHATTW=(1/(NTWPAIR-6))*DHATTTW*DHATTTW`;

PRINT GHATTW;

V=(1/NTWPAIR)*
INV((1/NTWPAIR)*(DX_1-
(NTW11+NTW12)*SU11-(NTW21+NTW22)*SU22-(NTW31+NTW32)*SU33-(NTW41+NTW42)*SU44-
(NTW51+NTW52)*SU55-(NTW61+NTW62)*SU66-(NTW71+NTW72)*SU77))*
GHATTW*
INV((1/NTWPAIR)*(DX_1-
(NTW11+NTW12)*SU11-(NTW21+NTW22)*SU22-(NTW31+NTW32)*SU33-(NTW41+NTW42)*SU44-
(NTW51+NTW52)*SU55-(NTW61+NTW62)*SU66-(NTW71+NTW72)*SU77));

PRINT V;

            */THE STANDARD ERRORS OF EACH ELEMENT IN THETA/*;
            */THE STANDARD ERRORS OF EACH ELEMENT IN THETA/*;
            */THE STANDARD ERRORS OF EACH ELEMENT IN THETA/*;

SETWINP=SQRT(VECDIAG(V));
PRINT SETWINP;

     */CONSTRUCT THE DIFFERENCE BETWEEN WAGE PREMIUM OF EACH LEVEL AND THE NEXT-TO-LOWER LEVEL/;
     */CONSTRUCT THE DIFFERENCE BETWEEN WAGE PREMIUM OF EACH LEVEL AND THE NEXT-TO-LOWER LEVEL/;
     */CONSTRUCT THE DIFFERENCE BETWEEN WAGE PREMIUM OF EACH LEVEL AND THE NEXT-TO-LOWER LEVEL/;

DBFEC2=TWINP[1,1]-0;
DBFEC3=TWINP[2,1]-TWINP[1,1];
DBFEC4=TWINP[3,1]-TWINP[2,1];
DBFEC5=TWINP[4,1]-TWINP[3,1];
DBFEC6=TWINP[5,1]-TWINP[4,1];
DBFEC7=TWINP[6,1]-TWINP[5,1];

DBFEC=DBFEC2||DBFEC3||DBFEC4||DBFEC5||DBFEC6||DBFEC7;

PRINT DBFEC;
             */THE VARIANCE MATRIX OF DBFEC/*;
             */THE VARIANCE MATRIX OF DBFEC/*;
             */THE VARIANCE MATRIX OF DBFEC/*;


     */FIRST CONSTRUCT THE VARIANCE OF EACH DBFECi/*;
     */FIRST CONSTRUCT THE VARIANCE OF EACH DBFECi/*;
     */FIRST CONSTRUCT THE VARIANCE OF EACH DBFECi/*;

VDB2=V[1,1];
VDB3=V[2,2]+V[1,1]-2*V[2,1];
VDB4=V[3,3]+V[2,2]-2*V[3,2];
VDB5=V[4,4]+V[3,3]-2*V[4,3];
VDB6=V[5,5]+V[4,4]-2*V[5,4];
VDB7=V[6,6]+V[5,5]-2*V[6,5];

SEDB2=SQRT(VDB2);
SEDB3=SQRT(VDB3);
SEDB4=SQRT(VDB4);
SEDB5=SQRT(VDB5);
SEDB6=SQRT(VDB6);
SEDB7=SQRT(VDB7);

PRINT SEDB2;
PRINT SEDB3;
PRINT SEDB4;
PRINT SEDB5;
PRINT SEDB6;
PRINT SEDB7;

    */SECOND CONSTRUCT THE COVARIANCES DBFECi,DBFECj/*;
    */SECOND CONSTRUCT THE COVARIANCES DBFECi,DBFECj/*;
    */SECOND CONSTRUCT THE COVARIANCES DBFECi,DBFECj/*;

CDB23=V[2,1]-V[1,1];
CDB24=V[3,1]-V[2,1];
CDB25=V[4,1]-V[3,1];
CDB26=V[5,1]-V[4,1];
CDB27=V[6,1]-V[5,1];

CDB32=CDB23;
CDB34=V[2,3]-V[2,2]-V[1,3]+V[1,2];
CDB35=V[2,4]-V[2,3]-V[1,4]+V[1,3];
CDB36=V[2,5]-V[2,4]-V[1,5]+V[1,4];
CDB37=V[2,6]-V[2,5]-V[1,6]+V[1,5];

CDB42=CDB24;
CDB43=CDB34;
CDB45=V[3,4]-V[3,3]-V[2,4]+V[2,3];
CDB46=V[3,5]-V[3,4]-V[2,5]+V[2,4];
CDB47=V[3,6]-V[3,5]-V[2,6]+V[2,5];

CDB52=CDB25;
CDB53=CDB35;
CDB54=CDB45;
CDB56=V[4,5]-V[4,4]-V[3,5]+V[3,4];
CDB57=V[4,6]-V[4,5]-V[3,6]+V[3,5];

CDB62=CDB26;
CDB63=CDB36;
CDB64=CDB46;
CDB65=CDB56;
CDB67=V[5,6]-V[5,5]-V[4,6]+V[4,5];

CDB72=CDB27;
CDB73=CDB37;
CDB74=CDB47;
CDB75=CDB57;
CDB76=CDB67;

          */THE ROWS OF THE MATRIX/*;
          */THE ROWS OF THE MATRIX/*;
          */THE ROWS OF THE MATRIX/*;

V_R1=VDB2||CDB23||CDB24||CDB25||CDB26||CDB27;
V_R2=CDB32||VDB3||CDB34||CDB35||CDB36||CDB37;
V_R3=CDB42||CDB43||VDB4||CDB45||CDB46||CDB47;
V_R4=CDB52||CDB53||CDB54||VDB5||CDB56||CDB57;
V_R5=CDB62||CDB63||CDB64||CDB65||VDB6||CDB67;
V_R6=CDB72||CDB73||CDB74||CDB75||CDB76||VDB7;


            */THE COMPLETE MATRIX/*;
            */THE COMPLETE MATRIX/*;
            */THE COMPLETE MATRIX/*;


V_=V_R1//V_R2//V_R3//V_R4//V_R5//V_R6;


PRINT V_;

            */THE STANDARD ERRORS/*;
            */THE STANDARD ERRORS/*;
            */THE STANDARD ERRORS/*;

SEDBFEC=SQRT(VECDIAG(V_));
PRINT SEDBFEC;


BFEC=TWINP;

          */THE RETURN TO ADDITIONAL SCHOOLING AT EACH SCHOOLING INCREMENT/*;
          */THE RETURN TO ADDITIONAL SCHOOLING AT EACH SCHOOLING INCREMENT/*;
          */THE RETURN TO ADDITIONAL SCHOOLING AT EACH SCHOOLING INCREMENT/*;

*/DIVIDE THE DIFFERENCED WAGE PREMIUMS WITH THE CORRESPONDING DIFFERENCES IN YEARS OF SCHOOLING/*;
*/DIVIDE THE DIFFERENCED WAGE PREMIUMS WITH THE CORRESPONDING DIFFERENCES IN YEARS OF SCHOOLING/*;
*/DIVIDE THE DIFFERENCED WAGE PREMIUMS WITH THE CORRESPONDING DIFFERENCES IN YEARS OF SCHOOLING/*;

BSTW2W=BFEC[1,1]/ALFA_21;
BSTW3W=(BFEC[2,1]-BFEC[1,1])/ALFA_32;
BSTW4W=(BFEC[3,1]-BFEC[2,1])/ALFA_43;
BSTW5W=(BFEC[4,1]-BFEC[3,1])/ALFA_54;
BSTW6W=(BFEC[5,1]-BFEC[4,1])/ALFA_65;
BSTW7W=(BFEC[6,1]-BFEC[5,1])/ALFA_76;

BSTWW=BSTW2W//BSTW3W//BSTW4W//BSTW5W//BSTW6W//BSTW7W;

PRINT BSTWW;

            */THE VARIANCE OF EACH BSTWiW/*;
            */THE VARIANCE OF EACH BSTWiW/*;
            */THE VARIANCE OF EACH BSTWiW/*;

VBSTW2W=(V_[1,1]/(ALFA_21**2))+((DBFEC2**2)*VALFA_[1,1])/((ALFA_21**2)*(ALFA_21**2));
VBSTW3W=(V_[2,2]/(ALFA_32**2))+((DBFEC3**2)*VALFA_[2,2])/((ALFA_32**2)*(ALFA_32**2));
VBSTW4W=(V_[3,3]/(ALFA_43**2))+((DBFEC4**2)*VALFA_[3,3])/((ALFA_43**2)*(ALFA_43**2));
VBSTW5W=(V_[4,4]/(ALFA_54**2))+((DBFEC5**2)*VALFA_[4,4])/((ALFA_54**2)*(ALFA_54**2));
VBSTW6W=(V_[5,5]/(ALFA_65**2))+((DBFEC6**2)*VALFA_[5,5])/((ALFA_65**2)*(ALFA_65**2));
VBSTW7W=(V_[6,6]/(ALFA_76**2))+((DBFEC7**2)*VALFA_[6,6])/((ALFA_76**2)*(ALFA_76**2));

        */THE CORRESPONDING STANDARD ERRORS/*;
        */THE CORRESPONDING STANDARD ERRORS/*;
        */THE CORRESPONDING STANDARD ERRORS/*;

SBSTW2W=SQRT(VBSTW2W);
SBSTW3W=SQRT(VBSTW3W);
SBSTW4W=SQRT(VBSTW4W);
SBSTW5W=SQRT(VBSTW5W);
SBSTW6W=SQRT(VBSTW6W);
SBSTW7W=SQRT(VBSTW7W);

PRINT SBSTW2W;
PRINT SBSTW3W;
PRINT SBSTW4W;
PRINT SBSTW5W;
PRINT SBSTW6W;
PRINT SBSTW7W;

  */ESTIMATE THE WAGE PREMIUMS RELATIVE TO "TRULY PRECEDING" LEVEL FOR LEVELS 4 AND 6/*;


DBFEC42=(BFEC[3,1]-BFEC[1,1]);
DBFEC64=(BFEC[5,1]-BFEC[3,1]);

BSTW42W=(BFEC[3,1]-BFEC[1,1])/ALFA_42;
BSTW64W=(BFEC[5,1]-BFEC[3,1])/ALFA_64;

PRINT BSTW42W;
PRINT BSTW64W;

*/THE CORRESPONDING STANDARD ERRORS/*;

VDB42=V[3,3]+V[1,1]-2*V[3,1];
VDB64=V[5,5]+V[3,3]-2*V[5,3];

VBSTW42W=(VDB42/(ALFA_42**2))+((DBFEC42**2)*VALFA_42)/((ALFA_42**2)*(ALFA_42**2));
VBSTW64W=(VDB64/(ALFA_64**2))+((DBFEC64**2)*VALFA_64)/((ALFA_64**2)*(ALFA_64**2));

SBSTW42W=SQRT(VBSTW42W);
SBSTW64W=SQRT(VBSTW64W);

PRINT SBSTW42W;
PRINT SBSTW64W;



  */WEIGH TOGETHER THE RETURN TO AT EACH SCHOOLING INCREMENT TO AN AVERAGE RETURN TO SCHOOLING/*;
  */WEIGH TOGETHER THE RETURN TO AT EACH SCHOOLING INCREMENT TO AN AVERAGE RETURN TO SCHOOLING/*;
  */WEIGH TOGETHER THE RETURN TO AT EACH SCHOOLING INCREMENT TO AN AVERAGE RETURN TO SCHOOLING/*;


    */WITH THE POPULATION-OLS WEIGHTING FUNCTION/*;
    */WITH THE POPULATION-OLS WEIGHTING FUNCTION/*;
    */WITH THE POPULATION-OLS WEIGHTING FUNCTION/*;

BSTWWO=
(BSTW2W*W1+BSTW3W*W2+BSTW4W*W3+BSTW5W*W4+BSTW6W*W5+BSTW7W*W6);

PRINT BSTWWO;


*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BSTWWO/*;
*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BSTWWO/*;
*/NOW START TO CONSTRUCT THE ESTIMATE OF THE VARIANCE COVARIANCE MATRIX OF THE ESTIMATOR BSTWWO/*;

                    */FIRST THE DERIVATIVES OF BSTWWO WITH RESPECT TO THi_jTW/*;
                    */FIRST THE DERIVATIVES OF BSTWWO WITH RESPECT TO THi_jTW/*;
                    */FIRST THE DERIVATIVES OF BSTWWO WITH RESPECT TO THi_jTW/*;

DTHBTWO=
(W1/ALFA_21)||(W2/ALFA_32)||(W3/ALFA_43)||
(W4/ALFA_54)||(W5/ALFA_65)||(W6/ALFA_76);

PRINT DTHBTWO;

                    */SECOND THE DERIVATIVE OF BSTWWO WITH RESPECT TO ALFA_ij/*;
                    */SECOND THE DERIVATIVE OF BSTWWO WITH RESPECT TO ALFA_ij/*;
                    */SECOND THE DERIVATIVE OF BSTWWO WITH RESPECT TO ALFA_ij/*;

                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;
                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;
                            */NOTE THE OLS-WEIGHTS ARE TREATED AS CONSTANTS!/*;

DABTWWO=
(W1*DBFEC2/(ALFA_21**2))||(W2*DBFEC3/(ALFA_32**2))||
(W3*DBFEC4/(ALFA_43**2))||(W4*DBFEC5/(ALFA_54**2))||
(W5*DBFEC6/(ALFA_65**2))||(W6*DBFEC7/(ALFA_76**2));

PRINT DABTWWO;

                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BSTWWO/*;
                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BSTWWO/*;
                */THIRD THE TAYLOR APPROXIMATION OF THE VARIANCE MATRIX OF BSTWWO/*;

VBSTWWO=(DTHBTWO*V_*DTHBTWO`)+(DABTWWO*VALFA_*DABTWWO`);

                                            */THE CORRESPONDING STANDARD ERRORS/*;
                                            */THE CORRESPONDING STANDARD ERRORS/*;
                                            */THE CORRESPONDING STANDARD ERRORS/*;

SBSTWWO=SQRT(VBSTWWO);

PRINT SBSTWWO;


*/--------------------------------------------------------------------------------------------/*;
*/--------------------------------------------------------------------------------------------/*;
*/--------------------------------------------------------------------------------------------/*;
*/--------------------------------------------------------------------------------------------/*;

*/--------------------------------------------------------------------------------------------/*;
*/--------------------------------------------------------------------------------------------/*;
*/--------------------------------------------------------------------------------------------/*;
*/--------------------------------------------------------------------------------------------/*;

      */THIS LAST PART OF THE PROGRAM COMPUTES CLASSICAL ERROR CORRECTIONS/*;
      */THIS LAST PART OF THE PROGRAM COMPUTES CLASSICAL ERROR CORRECTIONS/*;
      */THIS LAST PART OF THE PROGRAM COMPUTES CLASSICAL ERROR CORRECTIONS/*;
  

    */FIRST THE SLLS INFORMATION/*;

USE SPECB VAR{LINC};READ ALL INTO LINC;
USE SPECB VAR{AGE};READ ALL INTO AGE;
USE SPECB VAR{AGEQ};READ ALL INTO AGEQ;
USE SPECB VAR{SEX};READ ALL INTO SEXE;

    */ESTIMATE OF THE RELIABILITY RATIO IN THE CLASSICAL ERROR MODEL*/;
    */ESTIMATE OF THE RELIABILITY RATIO IN THE CLASSICAL ERROR MODEL*/;
    */ESTIMATE OF THE RELIABILITY RATIO IN THE CLASSICAL ERROR MODEL*/;

PRINT ALFA;

ALFAU=INV(XOBS`*XOBS)*XOBS`*S;
ALFAUT=ALFAU`;
ALFAA=ALFA;

PRINT ALFAU;
PRINT ALFAA;

ALFAABIG=ALFAA||ALFAA||ALFAA||ALFAA||ALFAA||ALFAA||ALFAA;
ALFAUBIG=ALFAUT//ALFAUT//ALFAUT//ALFAUT//ALFAUT//ALFAUT//ALFAUT;

SK_SU=ALFAABIG-ALFAUBIG;

PRINT SK_SU;

SK_SUQ=SK_SU#SK_SU;

PRINT SK_SUQ;

PRINT R;

VARERRLS=VECDIAG(SK_SUQ*R`)`*MJUHAT-(VECDIAG(SK_SU*R`)`*MJUHAT)**2;

PRINT VARERRLS;

SIMPLS=XOBS*ALFAU;

SIMPLSQ=SIMPLS#SIMPLS;

VARSSLLS=INV(NSLLS)*SUM(SIMPLSQ)-(INV(NSLLS)*SUM(SIMPLS))**2;

PRINT VARSSLLS;

RELRATLS=1-VARERRLS*(INV(VARSSLLS));

PRINT RELRATLS;

  */THIS PART OF THE PROGRAM COMPUTES THE CLASSICAL MEASUREMENT ERROR CORRECTION FOR THE SLLS/*;
  */THIS PART OF THE PROGRAM COMPUTES THE CLASSICAL MEASUREMENT ERROR CORRECTION FOR THE SLLS/*;
  */THIS PART OF THE PROGRAM COMPUTES THE CLASSICAL MEASUREMENT ERROR CORRECTION FOR THE SLLS/*;

                    */THE SAMPLE AVERAGE YEARS OF SCHOOLING/*;
                    */THE SAMPLE AVERAGE YEARS OF SCHOOLING/*;
                    */THE SAMPLE AVERAGE YEARS OF SCHOOLING/*;
SLSBAR=SUM(SIMPLS)/NSLLS;

PRINT SLSBAR;
                    */THE SAMPLE AVERAGE LOG EARNINGS/*;
                    */THE SAMPLE AVERAGE LOG EARNINGS/*;
                    */THE SAMPLE AVERAGE LOG EARNINGS/*;


YLSBAR=SUM(LINC)/NSLLS;

PRINT YLSBAR;

        */NOW I CONSTRUCT THE ESTIMATOR ON PAGE 107-108 IN FULLER (1987)/*;
        */NOW I CONSTRUCT THE ESTIMATOR ON PAGE 107-108 IN FULLER (1987)/*;
        */NOW I CONSTRUCT THE ESTIMATOR ON PAGE 107-108 IN FULLER (1987)/*;

INTSLLS=J(NSLLS,1,1);

XMATLS=INTSLLS||SIMPLS||AGE||AGEQ||SEXE;

MXXSLLS=(1/NSLLS)*XMATLS`*XMATLS;

MXYSLLS=(1/NSLLS)*XMATLS`*LINC;

VARSLS=(1/NSLLS)*((SIMPLS-SLSBAR)`*(SIMPLS-SLSBAR));

PRINT VARSLS;

ROWLS1=0||0||0||0||0;

ROWLS2=0||VARERRLS||0||0||0;

ROWLS3=0||0||0||0||0;

ROWLS4=0||0||0||0||0;

ROWLS5=0||0||0||0||0;

SuuLS=ROWLS1//ROWLS2//ROWLS3//ROWLS4//ROWLS5;

PRINT SuuLS;

XXSLS=MXXSLLS-SuuLS;

XXSLSI=INV(XXSLS);

BETA1LS=XXSLSI*MXYSLLS;

PRINT BETA1LS;

KLS=NCOL(XMATLS);

svvLS=(1/(NSLLS-KLS))*((LINC-XMATLS*BETA1LS)`*(LINC-XMATLS*BETA1LS));

VBETA1LS=(1/NSLLS)*(XXSLSI*svvLS+XXSLSI*(SuuLS*svvLS+(SuuLS*BETA1LS)*(BETA1LS`*SuuLS`))*XXSLSI);

PRINT VBETA1LS;

DIAGLS=VECDIAG(VBETA1LS);

RDIAGLS=SQRT(DIAGLS);

PRINT RDIAGLS;

*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;
*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;
*/TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS TWINS/*;
 
USE J VAR{LAINK};READ ALL INTO Y;
USE J VAR{AGE};READ ALL INTO AGE;
USE J VAR{AGEQ};READ ALL INTO AGEQ;
USE J VAR{SEXE};READ ALL INTO SEXE;


    */ESTIMATE OF THE RELIABILITY RATIO IN THE CLASSICAL ERROR MODEL*/;

VARERR=VECDIAG(SK_SUQ*R`)`*MJUHATTW-(VECDIAG(SK_SU*R`)`*MJUHATTW)**2;

  */THE MEASUREMENT ERROR VARIANCE/*;

PRINT VARERR;

SIMP=XOBSTW*ALFAU;

SIMPQ=SIMP#SIMP;

VARSTW=INV(NTW)*SUM(SIMPQ)-(INV(NTW)*SUM(SIMP))**2;

PRINT VARSTW;

RELRAT=1-VARERR*(INV(VARSTW));

PRINT RELRAT;




                    */THE NO OF OBSERVATIONS/*;
                    */THE NO OF OBSERVATIONS/*;
                    */THE NO OF OBSERVATIONS/*;

N=NROW(Y);

PRINT N;

                    */THE SAMPLE AVERAGE YEARS OF SCHOOLING/*;
                    */THE SAMPLE AVERAGE YEARS OF SCHOOLING/*;
                    */THE SAMPLE AVERAGE YEARS OF SCHOOLING/*;


SBAR=SUM(SIMP)/N;

PRINT SBAR;
                    */THE SAMPLE AVERAGE LOG EARNINGS/*;
                    */THE SAMPLE AVERAGE LOG EARNINGS/*;
                    */THE SAMPLE AVERAGE LOG EARNINGS/*;


YBAR=SUM(Y)/N;

PRINT YBAR;

        */NOW I CONSTRUCT THE ESTIMATOR ON PAGE 107-108 IN FULLER (1987)/*;
        */NOW I CONSTRUCT THE ESTIMATOR ON PAGE 107-108 IN FULLER (1987)/*;
        */NOW I CONSTRUCT THE ESTIMATOR ON PAGE 107-108 IN FULLER (1987)/*;

INT=J(N,1,1);

XMAT=INT||SIMP||AGE||AGEQ||SEXE;

MXX=(1/N)*XMAT`*XMAT;

MXY=(1/N)*XMAT`*Y;

ROW1=0||0||0||0||0;
KOL1=ROW1`;

ROW2=0||VARERR||0||0||0;
KOL2=ROW2`;

ROW3=0||0||0||0||0;
KOL3=ROW3`;

ROW4=0||0||0||0||0;
KOL4=ROW4`;

ROW5=0||0||0||0||0;
KOL5=ROW5`;

Suu=KOL1||KOL2||KOL3||KOL4||KOL5;

PRINT Suu;

XXS=MXX-Suu;

XXSI=INV(XXS);

BETA1=XXSI*MXY;

PRINT BETA1;

K=NCOL(XMAT);

svv=(1/(N-K))*((Y-XMAT*BETA1)`*(Y-XMAT*BETA1));

VBETA1=(1/N)*(XXSI*svv+XXSI*(Suu*svv+(Suu*BETA1)*(BETA1`*Suu`))*XXSI);

PRINT VBETA1;

DIAG=VECDIAG(VBETA1);

RDIAG=SQRT(DIAG);

PRINT RDIAG;

    */TWIN-BASED EQUATION/*;
    */TWIN-BASED EQUATION/*;
    */TWIN-BASED EQUATION/*;

XOBSTW1=EDU11||EDU21||EDU31||EDU41||EDU51||EDU61||EDU71;
XOBSTW2=EDU12||EDU22||EDU32||EDU42||EDU52||EDU62||EDU72;

SIMP1=XOBSTW1*ALFAU;
SIMP2=XOBSTW2*ALFAU;

DSIMP=SIMP1||SIMP2;

DS=SIMP1-SIMP2;

SuuWTW=2*VARERR;

PRINT SuuWTW;

MXXWTW=INV(NTWPAIR)*(DS`*DS);

PRINT MXXWTW;

XXSWTW=MXXWTW-SuuWTW;

MXYWTW=INV(NTWPAIR)*DS`*DY;

BETA1WTW=INV(XXSWTW)*MXYWTW;

PRINT BETA1WTW;

svvtw=INV(NTWPAIR-NCOL(DS))*((DY-DS*BETA1WTW)`*(DY-DS*BETA1WTW));

VBRWTW=INV(NTWPAIR)*
(INV(XXSWTW)*(svvtw)+
INV(XXSWTW)*(SuuWTW*svvtw+(SuuWTW*BETA1WTW)*(BETA1WTW`*SuuWTW`))*INV(XXSWTW));

PRINT VBRWTW;

SEBRWTW=SQRT(VECDIAG(VBRWTW));

PRINT SEBRWTW;

RELDWTW=((BETA1WTW-BSTWWO)/BETA1WTW)*100;

PRINT RELDWTW;

*--------------------------------/SPLINE REGRESSIONS/--------------------------------*;
*--------------------------------/SPLINE REGRESSIONS/--------------------------------*;
*--------------------------------/SPLINE REGRESSIONS/--------------------------------*;

PRINT ALFAU;

ALFAU_21=ALFAU[2,1]-ALFAU[1,1];
ALFAU_32=ALFAU[3,1]-ALFAU[2,1];
ALFAU_43=ALFAU[4,1]-ALFAU[3,1];
ALFAU_54=ALFAU[5,1]-ALFAU[4,1];
ALFAU_65=ALFAU[6,1]-ALFAU[5,1];
ALFAU_76=ALFAU[7,1]-ALFAU[6,1];
      */THE SLLS/*;

DSPL=
(ALFAU_21||0||0||0||0||0)//(ALFAU_21||ALFAU_32||0||0||0||0)//
(ALFAU_21||ALFAU_32||ALFAU_43||0||0||0)//(ALFAU_21||ALFAU_32||ALFAU_43||ALFAU_54||0||0)//
(ALFAU_21||ALFAU_32||ALFAU_43||ALFAU_54||ALFAU_65||0)//
(ALFAU_21||ALFAU_32||ALFAU_43||ALFAU_54||ALFAU_65||ALFAU_76);

      */THE SLLS/*;

USE SPECB VAR{LINC};READ ALL INTO LINC;
USE SPECB VAR{AGE};READ ALL INTO AGE;
USE SPECB VAR{AGEQ};READ ALL INTO AGEQ;
USE SPECB VAR{SEX};READ ALL INTO SEXE;

SPLINES=XOBS[1:NSLLS,2:7]*DSPL;

XSPLINE=INTSLLS||SPLINES||AGE||AGEQ||SEXE;
XREST=INTSLLS||SIMPLS||AGE||AGEQ||SEXE;

SPLINELS=INV(XSPLINE`*XSPLINE)*XSPLINE`*LINC;
XRESTLS=INV(XREST`*XREST)*XREST`*LINC;

PRINT SPLINELS;
PRINT XRESTLS;
    */F-TEST/*;

RESPLINE=LINC-XSPLINE*SPLINELS;
RESSPLINQ=RESPLINE`*RESPLINE;
RESREST=LINC-XREST*XRESTLS;
RESRESTQ=RESREST`*RESREST;

F_TEST=((RESRESTQ-RESSPLINQ)/5)/(RESSPLINQ/(NSLLS-10));
PRINT F_TEST;


      */THE TWINS/*;

USE J VAR{LAINK};READ ALL INTO Y;
USE J VAR{AGE};READ ALL INTO AGE;
USE J VAR{AGEQ};READ ALL INTO AGEQ;
USE J VAR{SEXE};READ ALL INTO SEXE;

SPLINES=XOBSTW[1:NTW,2:7]*DSPL;

XSPLINE=INTTW||SPLINES||AGE||AGEQ||SEXE;
XREST=INTTW||SIMP||AGE||AGEQ||SEXE;

SPLINELS=INV(XSPLINE`*XSPLINE)*XSPLINE`*LAINK;
XRESTLS=INV(XREST`*XREST)*XREST`*LAINK;

PRINT SPLINELS;
PRINT XRESTLS;
    */F-TEST/*;

RESPLINE=LAINK-XSPLINE*SPLINELS;
RESSPLINQ=RESPLINE`*RESPLINE;
RESREST=LAINK-XREST*XRESTLS;
RESRESTQ=RESREST`*RESREST;

F_TEST=((RESRESTQ-RESSPLINQ)/5)/(RESSPLINQ/(NTW-10));
PRINT F_TEST;

QUIT;
RUN;