» NOTE ON WEIGHTS

        NOTE ON USE OF WEIGHTS:
        ~~~~~~~~~~~~~~~~~~~~~~

        THERE ARE 6 WEIGHT VARIABLES IN THE CUMULATIVE DATA FILE:

                  VCF0009          VCF0010         VCF0011
                  VCF0009a         VCF0010a        VCF0011a

        1.  IMPORTANT:  CASES FROM YEARS OTHER THAN 1970 AND 1994-LATER
            HAVE IDENTICAL VALUES IN ALL (6) WEIGHT VARIABLES.  WHEN DATA
            FOR YEARS EXCLUDING 1970 AND 1994-LATER ARE USED FROM THE
            CUMULATIVE DATA FILE, ANY OF THESE WEIGHT VARIABLES MAY BE
            UTILIZED TO OBTAIN THE SAME RESULTS.

        2.  WHEN CUMULATIVE DATA FILE VARIABLES INCLUDE 1970 DATA AND/OR
            DATA FROM 1994 AND LATER, WEIGHT SELECTION SHOULD BE BASED 
            UPON 2 CONDITIONS:
                A) THE 'TYPE' OF 1970 VARIABLE
                B) WHETHER POST-STRATIFIED OR NON-POST-STRATIFIED WEIGHTING
                   IS USED 1994 AND LATER
 
            2a.
            NOTES CONCERNING 1970
            ---------------------

            The original study data for 1970 were weighted by variable
            type; there were 3 types of 1970 variables:  Type 0, Type 1,
            Type 2.

            Most 1970 variables were Type 0. 1970 Type 1 or 1970 Type 2 
            data are identified in documentation; all other Cumulative Data
            File variables that include 1970 data and not specifying otherwise 
            are assumed to be Type 0 data for 1970.

            Weighting Cumulative Data File variables that include 1970
            data means selecting the appropriate weight for the type of
            1970 variable represented in the variable.
            For each of the 3 types of 1970 variables, there are 2
            Cumulative Data File weight variables which have identical
            values for 1970 cases:

                  CDF VAR           CDF VAR           CDF VAR
                  INCLUDES 1970     INCLUDES 1970     INCLUDES 1970
                  TYPE 0 DATA -     TYPE 1 DATA -     TYPE 2 DATA -
                  USE ONE OF:       USE ONE OF:       USE ONE OF:
                  ~~~~~~~~~~~       ~~~~~~~~~~~       ~~~~~~~~~~~
                    VCF0009           VCF0010         VCF0011
                    VCF0009a          VCF0010a        VCF0011a

            If no 1994 or later cases are selected in combination with 1970
            cases, then it does not matter which of the 2 weight variables
            for that 'type' is used.  For example:  if 1970 data are Type 0
            and no 1994 or later data are included, then either VCF0009 or
            VCF0009a can be used to produce the same results. Choice among 
            the 2 variables for each 1970 'type' is determined by the kind 
            of weighting desired for years 1994 and later (2b).


            2b.
            NOTES FOR 1994 AND LATER (Post-stratified weights available)
            ------------------------------------------------------------

            1994 and later data have more than one type of weighting
            available:

                 1994-LATER
                 WEIGHTING TYPE                WEIGHT VALUES SAME IN 3 VARS:
                 ~~~~~~~~~~~~~~                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
              1. NOT POST-STRATIFIED           VCF0009,  VCF0010,  VCF0011
              2. POST-STRATIFIED               VCF0009a, VCF0010a, VCF0011a

            In Pre-Post studies after 1994, there were 2 post-stratified
            weights, one for pre-election variables from Pre-Post studies 
            and one for post-election variables from Pre-Post studies.
            Cumulative Data File "a" weight variables (VCF0009a,VCF0010a,
            VCF0011a -- identical to one another for these years) correspond
            to the 'pre' post-stratified weights from these years. 
            Note: although the post-election post-stratified weights provide
            the most complete adjustment for post-election variables from
            pre-post studies after 1994, the difference in estimates produced
            using pre-election post-stratified weighting versus post-election
            post-stratified weighting for post-election variables is small
            enough to justify using pre-election post-stratified weights 
            (VCF0009a,VCF0010a,VCF0011a) for all data when post-stratification
            adjustments are desired.

 
        ADDITIONAL NOTES
        ~~~~~~~~~~~~~~~~

        1970 notes:
           Black respondents were asked all questions.  White respondents
           were assigned to one of two formats of the questionnaire.  Each
           format of questionnaire excluded a selection of questions if the
           respondent was white; the questions excluded differed in each
           format.  The two formats of the questionnaire were designated
           Form 1 and Form 2.
           'Type 0' describes variables for questions which were not excluded
           in either questionnaire format.  'Type 1' describes variables for
           questions excluded from Form 2, and 'Type 2' describes variables
           for questions excluded from Form 1.

           All 1970 vars not listed in VCF0010 as type 1 or in VCF0011 as type
           2 are type 0; documentation for each Cumulative Data File variable
           in this codebook provides the type of 1970 data utilized (if any).

        1994 and later notes:
           The first time-series weight variables produced for the 1994 and
           1996 studies did not correct for an under-representation in Study
           data of younger and less-educated respondents (primarily an effect
           of the empaneling design used 1992 to 1996; see the 1994 and 1996
           codebook special weight documentation).  New weight variables were
           therefore produced, constructed to post-stratify the NES data to 
           match the Current Population Study (CPS) estimate of the
           distribution of age group by education level.  After 1996, the 
           same type of post-stratified weights continued to be constructed.