Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

National Evaluation of Welfare-to-Work Strategies: 2-Year Full Impact Sample Files: Background information on estimating program impacts

 ******************************************************************************                                 HOW MDRC ESTIMATED IMPACTS  *****************************************************************************;  **** MDRC 2/01 FOR ALL SITES:  **** MDRC 2/01: This is the standard list of baseline demographic covariates for the impact regression model:                   MARSTAT    /* SINGLE PARENT, EVER MARRIED */                 TWOCHILD   /* TWO CHILDREN                */                 THRCHILD   /* THREE OR MORE CHILDREN      */                 CHLD0T5    /* ANY CHILD 0-5 YEARS OLD     */                 BLACK      /* BLACK                       */                 NOTBW      /* NOT BLACK OR WHITE          */                 AGEP       /* AGE AT RANDOM ASSIGNMENT    */                 FEMALE     /* FEMALE                      */                 HSDIP      /* HS DIPLOMA-GED              */  ;  Some sample members have missing values for these measures. These must be imputed prior to calculating impacts.  The public use file contains imputed values for these measures based on mean substituion by local office and sample member's educational attainment at random assignment.  (The imputed values are decimals between 0 and 1.)  If you choose to use MDRC's imputations, substitute                  XMARSTAT    /* SINGLE PARENT, EVER MARRIED */                XTWOCHLD    /* TWO CHILDREN                */                XTHRCHLD    /* THREE OR MORE CHILDREN      */                XCHLD0T5    /* ANY CHILD 0-5 YEARS OLD     */                XBLACK      /* BLACK                       */                XNOTBW      /* NOT BLACK OR WHITE          */                XAGEP       /* AGE AT RANDOM ASSIGNMENT    */                XFEMALE     /* FEMALE                      */                XHSDIP      /* HS DIPLOMA-GED              */  ;    **** MDRC 2/01: COVARIATES CALCULATES FROM ADMINISTRATIVE RECORDS This is the standard list of covariates created from administrative records:                  YREMP      /*  EMPLOYED IN YEAR PRIOR TO RA?               */                 EMPPQ1     /*  EMPLOYED IN PRE-RA QUARTER 1                */                 YREARN     /*  YEAR PRIOR TO RA EARNINGS                   */                 YREARNSQ   /*  YEAR PRIOR TO RA EARNINGS SQUARED           */                 PEARN1     /*  EARNINGS: RELATIVE PRE-RA QUARTER 1         */                 RECPC1     /*  RECEIVED AFDC IN FISC QTR 1 BEFORE RA       */                 YRREC      /*  RECEIVED AFDC DURING YEAR PRIOR TO RA?      */                 GYRADC     /*  AVG AFDC PER MTH RECVED YEAR PRIOR TO RA    */                 YRKREC     /*  # OF MTHS RECEIVED AFDC YEAR PRIOR TO RA    */                 YRRFS      /*  RECEIVED FOOD STAMPS YEAR PRIOR TO RA?      */                 GYRFS      /*  AVERAGE FOOD STAMPS PER MONTH RECEIVED      */                 YRKRFS     /*  NUMBER OF MONTHS RECEIVING FS PRIOR YEAR    */ ;  There are no missing values for these measures.   *****************************************************************************************        TO ESTIMATE IMPACTS FOR THE ATLANTA AND GRAND RAPIDS LFA AND HCD APPROACHES:  *****************************************************************************************;  For Atlanta:  select ALPHSITE=1  For Grand Rapids: select ALPHSITE=4    **** MDRC 2/01: RESEARCH GROUP DUMMY VARIABLES ;                   B          /*  HUMAN CAPITAL DEVELOPMENT GROUP  */                 J          /*  LABOR FORCE ATTACHMENT GROUP     */                 C2         /*  CONTROL GROUP                    */   ;    **** MDRC 2/01: CALCULATE THE MEANS OF DEPENDENT VARIABLES AND RESEARCH GROUP DUMMIES                 AND COVARIATES;   **** MDRC 2/01: MDRC RAN OLS REGRESSIONS;   [Dependent variable]= B+J+[baseline demographic covariates]+ [administrative records covariates]   and included an F-Test to determine whether the differences in impacts between LFA and HCD were statistically significant.    **** MDRC 2/01 The regression coefficients associated with the dummy vaiables B and J show the impacts of the HCD and LFA programs, respectively.  The report tables show adjusted means.  To estimate adjusted means for each dependent variable:  1) Adjusted mean for control group=  ADJMEANC=  GDEPVAR -       (COEFOFB        * MEANOFB) -    (COEFOFJ        * MEANOFJ)  site mean       HCD impact=     proportion      LFA impact=     proportion of dependent    coefficient     of HCDs in      coefficient     of LFAs in variable        of B from       the sample=     of J from       the sample= from            regression      Mean of B       regression      Mean of J MEANS           output          from            output          from output                          MEANS                           MEANS                                 output                          output   2) Adjusted mean for HCD group=  ADJMEANB        =       ADJMEANC      +       COEFOFB     3) Adjusted mean for LFA group=  ADJMEANJ        =       ADJMEANC      +       COEFOFJ     *****************************************************************************************        TO ESTIMATE IMPACTS FOR THE RIVERSIDE LFA APPROACH:   *****************************************************************************************;  NOTE: Estimating impacts for Riverside LFA is relatively complex because Riverside's       research design involved different sampling ratios for sample members determined        to need basic education:       1/3 LFA   1/3  HCD    1/3 Control        not to need basic education:   1/2 LFA     0  HCD    1/2 Control   Where need for basic education=  no high school diploma or GED certificate (HSDIP=0)  OR  below minimum score on baseline literacy test (LOWREAD=1)  OR  below minimum score on baseline math test (LOWMATH=1)  OR  non-English speaker (LIMENG=1)    In Riverside the proportion of in-need and not in-need for the full impact sample=  TABLE OF NONEEDP BY RES2  NONEEDP(Riv temp - No Need of ED)           RES2(Research Group-phone2) Frequency Percent Row Pct Col Pct    2:HCD    3:LFA    6:CTL     Total                1596     1586     1539     4721             19.18    19.06    18.49    56.73 IN-NEED     33.81    33.59    32.60            100.00    46.87    46.05                  0     1798     1803     3601 NOT          0.00    21.61    21.67    43.27 IN-NEED      0.00    49.93    50.07              0.00    53.13    53.95  Total        1596     3384     3342     8322             19.18    40.66    40.16   100.00   It should be expected that impacts for LFA for the in-need group will differ from impacts for the not-in-need group  (see impact tables).   IMPORTANT!!!:  To make the impacts for LFA generalizable to the full impact sample, it is necessary to  1) Weight the results for in-need to equal 56.73 percent of the full sample impact  2) Weight the results for not-in-need to equal 43.27 percent of the full sample impact   NOTE: This weighting strategy should be repeated (but with different weights) when running impacts for subgroups, because the proportions of in-need and not in-need will vary.  There are a number of ways to implement this weighting strategy:    MDRC chose to apply the weights after impacts were run:    Select: ALPHSITE=7  Include all LFAs, HCDs, and control group members in the calculations.   Include an extra series of baseline demographic covariates:             NEED           /* =1 if in-need of basic education     */    *MDRC 2/01 Variables in the NEEDCOV series will be part of the Riverside LFA            regression model.  They should correspond exactly to the vars in the            standard series except for HSDIP (see above note for more info).            Whenever you add/delete vars to/from the standard list, be sure            to also add/delete the corresponding vars to/from the extra list. ;                         /* Additional covariates for the         */         nYREMP         /* Riverside LFA regression model.       */         nEMPPQ1        /* They are the cross products of the    */         nYREARN        /* dummy variable NEED (=1 if in need of */         nYRERNSQ       /* basic education, else=0)              */         nPEARN1        /* and each of the standard covariates.  */         nRECPC1         nYRREC         nGYRADC         nYRKREC         nYRRFS         nGYRFS         nYRKRFS         nMARSTAT         nTWOCHLD         nTHRCHLD         nCHLD0T5         nBLACK         nNOTBW         nAGEP         nFEMALE ;    **** MDRC 2/01: RESEARCH GROUP DUMMY VARIABLES ;            BNEED      /*  HCD IN NEED OF BASIC EDUCATION (100% OF HCDs)  */           JNEED      /*  LFA IN NEED OF BASIC EDUCATION   */           JNONEED    /*  LFA NOT IN NEED OF BASIC EDUCATION   */           C2         /*  CONTROL GROUP                    */   ;     **** MDRC 2/01: CALCULATE THE MEANS OF DEPENDENT VARIABLES AND RESEARCH GROUP DUMMIES                 AND COVARIATES THREE TIMES:  1) Include all LFAs, HCDs, and control group members  2) Include only LFAs, HCDs, and control group members in need of basic education (NEED=1)  3) Include only LFAs and control group members not in need of basic education (NEED=0)   **** MDRC 2/01: MDRC RAN OLS REGRESSIONS;   [Dependent variable]= BNEED     +                       JNEED     +                       JNONEED   +                       [baseline demographic covariates]   +                       [administrative records covariates] +                       NEED      +                       [NEEDCOV  covariates ]    Note:  MDRC included HCDs in the regression but DID NOT report the impacts and        adjusted means for HCDs from the output.         See below:              TO ESTIMATE IMPACTS FOR THE RIVERSIDE HCD APPROACH AND             FOR THE LFA APPROACH FOR SAMPLE MEMBERS IN NEED OF BASIC EDUCATION         for more information.   **********************************************************************      TO CALCULATE WEIGHTED IMPACTS, SIGNIFICANCE     LEVELS, AND WEIGHTED MEANS FOR THE RIVERSIDE LFA PROGRAM.  *********************************************************************      Let      NJIMP =   the average impact for LFAs      JinIMP=   the average impact for LFAs in need of basic education               (the coefficient of JNEED)      INNEEDWT= the proportion of the full sample               in need of basic education (from MEANS output)      JnoIMP=   the average impact for LFAs not in need of basic education               (the coefficient of JNONEED)      NONEEDWT= the proportion of the full sample               not in need of basic education (from MEANS output)      Steps A and B calculate the weighted impact for LFAs   A.  The LFA impact is the weighted average of the in need     LFA impact and the not in need LFA impact. You will need     to calculate these weighted means with a spreadsheet, calculator, or     through additional programming, using the following formulas:        The  weighted LFA impact=      NJIMP = (INNEEDWT*JINIMP) + (NONEEDWT*JNOIMP)      B.  To determine whether weighted impacts are significant, use the     F statistic for the model that tests whether the weighted in need     and not in need impacts are significant:      TEST  INNEEDWT*JNEED + NONEEDWT*JNONEED = 0   Steps C through E calculate the adjusted means for control group members:  Let:     CMEAN=    the adjusted mean for control group members      CMEANIN=  the adjusted mean for control group members in need of basic education (NEED=1)      CMEANNOT= the adjusted mean for control group members               not in need of basic education (NEED=0)      MEANNEED= the unadjusted mean of the dependent variable for all LFAs, HCDs, and               control group members in need of basic education (NEED=1)      MEANNOT=  the unadjusted mean of the dependent variable for all LFAs and               control group members not in need of basic education (NEED=0)       JINSHARE= the proportion of LFAs in the in-need sample (NEED=1)      JNOSHARE= the proportion of LFAs in the not in-need sample (NEED=0)      BIMP=     the average impact for HCDs  (the coefficient for BNEED)      HCDSHARE= the proportion of HCDs in the in-need sample (NEED=1)     C.  Calculate the adjusted Control mean for the in need sample.     Subtract the following from the mean of the in need sample:     (See formula below.)         (1) the proportion of LFAs in the in need sample multiplied by the            impact for the in need sample, and         (2) the proportion of HCDs in the in need sample multiplied by            the HCD impact.         CMEANIN = MEANNEED - (JINSHARE*JINIMP) - (HCDSHARE*BIMP)  D.  Calculate the adjusted Control mean for the not in need sample.     Subtract the percent of LFAs in the not in need sample multiplied by the     impact for the not in need sample from the mean of the not in     need sample.         CMEANNOT= MEANNOT  - (JNOSHARE*JNOIMP)  E.  Calculate the weighted Control mean for the full LFA sample.     Add the control mean of the in need sample multiplied by the in     need weight to the control mean of the not in need sample multiplied     by the not in need weight.         CMEAN = INNEEDWT*CMEANIN + NONEEDWT*CMEANNOT   Steps F through H calculate the adjusted means for LFAs:   Let:     JMEAN=    the adjusted mean for all LFAs      JMEANIN=  the adjusted mean for LFAs in need of basic education (NEED=1)      JMEANNOT= the adjusted mean for LFAs not in need of basic education (NEED=0)   F. Calculate the adjusted LFA full sample mean. Add the weighted    Control mean to the weighted LFA impact for the full sample.       JMEAN = CMEAN + NJIMP   FYI:   G. Calculate the adjusted LFA mean for the in need sample. Add the    adjusted Control mean of the in need sample to the in need LFA impact.       JMEANIN = CMEANIN  + JINIMP  H. Calculate the adjusted LFA mean for the not in need sample. Add the    adjusted Control mean of the not in need sample to the not in need    LFA impact.       JMEANNOT= CMEANNOT + JNOIMP    I. To calculate the percentage change of the impact (PJIMP) divide the weighted    LFA impact by the weighted Control mean and multiply by 100.            PJIMP = (NJIMP / CMEAN) * 100    NOTE: It is also possible to weight the sample ahead of time and run PROC GLM weighted (in SAS) or its equivalent in other statistical packages.  The file includes the weight variable RILFACW with the following values for the full sample:   The formula for the weight=   /* see table above */   HCDs:                    1.00  LFA IN-NEED:             56.73 / 46.87 = 1.21041266  LFA NOT-IN-NEED:         43.27 / 53.13 = 0.81439683  CONTROL IN NEED:         56.73 / 46.05 = 1.23189619  CONTROL NOT-IN-NEED:     43.27 / 53.95 = 0.80205865   After weighting LFAs and control group members have the same proportion of in-need and not in-need as the full sample (LFA+HCD+control group combined).   But this weight variable can only be used for estimating impacts for the full sample. A different weight would need to be calculated for estimating impacts for subgroups, because the proportion of in-need and not in-need will vary.     *****************************************************************************************               TO ESTIMATE IMPACTS FOR THE RIVERSIDE HCD APPROACH AND             FOR THE LFA APPROACH FOR SAMPLE MEMBERS IN NEED OF BASIC EDUCATION   *****************************************************************************************   IMPORTANT !!!:  ONLY SAMPLE MEMBERS IN NEED OF BASIC EDUCATION SHOULD BE INCLUDED                 IN THE CALCULATIONS   Select: ALPHSITE=7  AND NEED=1   MDRC deleted HSDIP from the standard list of baseline demographic covariates when estimating impacts for HCD and LFA in-need. The vast majority  of in-need sample members do not have a HS DIPLOMA or GED (HSDIP=0), and HSDIP is highly correlated with other independent variables.  All other covars for Riverside HCDs are the same as those of other sites.   **** MDRC 2/01: RESEARCH GROUP DUMMY VARIABLES ;                   B          /*  HUMAN CAPITAL DEVELOPMENT GROUP  */                 J          /*  LABOR FORCE ATTACHMENT GROUP     */                 C2         /*  CONTROL GROUP                    */   ;   **** MDRC 2/01: CALCULATE THE MEANS OF DEPENDENT VARIABLES AND RESEARCH GROUP DUMMIES                 AND COVARIATES;   **** MDRC 2/01: MDRC RAN OLS REGRESSIONS;   [Dependent variable]= B+J+[baseline demographic covariates]+ [administrative records covariates]   and included an F-Test to determine whether the differences in impacts between LFA and HCD were statistically significant.    **** MDRC 2/01 The regression coefficients associated with the dummy vaiables B and J show the impacts of the HCD and LFA programs, respectively.  The report tables show adjusted means.  To estimate adjusted means for each dependent variable:  1) Adjusted mean for control group=  ADJMEANC=  GDEPVAR -       (COEFOFB        * MEANOFB) -    (COEFOFJ        * MEANOFJ)  site mean       HCD impact=     proportion      LFA impact=     proportion of dependent    coefficient     of HCDs in      coefficient     of LFAs in variable        of B from       the sample=     of J from       the sample= from            regression      Mean of B       regression      Mean of J MEANS           output          from            output          from output                          MEANS                           MEANS                                 output                          output   2) Adjusted mean for HCD group=  ADJMEANB        =       ADJMEANC      +       COEFOFB     3) Adjusted mean for LFA group=  ADJMEANJ        =       ADJMEANC      +       COEFOFJ                       *****************************************************************************************          TO ESTIMATE IMPACTS FOR THE COLUMBUS INTEGRATED AND TRADITIONAL APPROACHES:   *****************************************************************************************;   Select ALPHSITE=2    **** MDRC 2/01: RESEARCH GROUP DUMMY VARIABLES ;                   I          /*  INTEGRATED CASE MANAGEMENT GROUP */                 T          /*  TRADITIONAL CASE MANAGEMENT GROUP*/                 C2         /*  CONTROL GROUP                    */   ;   **** MDRC 2/01: CALCULATE THE MEANS OF DEPENDENT VARIABLES AND RESEARCH GROUP DUMMIES                 AND COVARIATES;   **** MDRC 2/01: MDRC RAN OLS REGRESSIONS;   [Dependent variable]= I+T+[baseline demographic covariates]+[administrative records covariates]   and included an F-Test to determine whether the differences in impacts between INTEGRATED and TRADITIONAL were statistically significant.    **** MDRC 2/01 The regression coefficients associated with the dummy vaiables I and T show the impacts of the INTEGRATED and TRADITIONAL programs, respectively.  The report tables show adjusted means.  To estimate adjusted means for each dependent variable:  **** MDRC 2/01 The regression coefficients associated with the dummy vaiables I and T show the impacts of the INTEGRATED and TRADITIONAL programs, respectively.  To estimate adjusted means for each dependent variable:  1) Adjusted mean for control group=  ADJMEANC=  GDEPVAR -       (COEFOFI        * MEANOFI) -    (COEFOFT        * MEANOFT)  site mean       I impact=       proportion      T impact=       proportion of dependent    coefficient     of I's in       coefficient     of Ts in variable        of I from       the sample=     of T from       the sample= from            regression      Mean of I       regression      Mean of T MEANS           output          from            output          from output                          MEANS                           MEANS                                 output                          output   2) Adjusted mean for INTEGRATED group=  ADJMEANI        =       ADJMEANC      +       COEFOFI     3) Adjusted mean for TRADITIONAL group=  ADJMEANT        =       ADJMEANC      +       COEFOFT       *****************************************************************************************        TO ESTIMATE IMPACTS FOR THE DETROIT, OKLAHOMA CITY, AND PORTLAND PROGRAMS:   *****************************************************************************************;   For Detroit: Select ALPHSITE=3  For Oklahoma City: Select ALPHSITE=5  For Portland: Select ALPHSITE=6   **** MDRC 2/01  FOR PORTLAND ONLY:  Add to list of background demographic covariates:  PORTCOH2          /* randomly assigned after change in random assignment ratio   */     **** MDRC 2/01: RESEARCH GROUP DUMMY VARIABLES ;                   P          /*  PROGRAM GROUP                    */                 C2         /*  CONTROL GROUP                    */   ;       **** MDRC 2/01: CALCULATE THE MEANS OF DEPENDENT VARIABLES AND RESEARCH GROUP DUMMIES                 AND COVARIATES;   **** MDRC 2/01: MDRC RAN OLS REGRESSIONS;   [Dependent variable]= P  [baseline demographic covariates] [administrative records covariates]    **** MDRC 2/01 The regression coefficients associated with the dummy vaiable P shows the impact of the Program on the program group.  To estimate adjusted means for each dependent variable:  1) Adjusted mean for control group=  ADJMEANC=  GDEPVAR -       (COEFOFP           * MEANOFP)  site mean       Program impact=    proportion of dependent    coefficient        of P's in variable        of P from          the sample= from            regression         Mean of P MEANS           output             from output                             MEANS                                    output   2) Adjusted mean for Program group=  ADJMEANP        =       ADJMEANC      +       COEFOFP