Survey of Program Dynamics (SPD)

The primary goals of the SPD are to provide information on spells of actual and potential program participation over a ten-year period, 1992 to 2001, and to examine the causes of program participation and its long-term effects on the well-being of recipients, their families, and their children.

Note

¹The third longitudinal related data files contain data from the 1992, 1993, 1994, 1996, 1997, 1998, 1999, 2000, and 2001.
²A revised data dictionary and data file were released on March 7, 2006. In the previous SPD 3rd longitudinal file, people who permanently left the universe were incorrectly classified as "longitudinally non-interviewed." Zero weights were given to people who were qualified to be classified as longitudinally interviewed until they died or permanently moved outside the survey universe, and through the non-interview adjustment, others in the sample were weighted up to account for them. This error creates a bias by transferring the weights of these dead and out-of-universe people to the living, longitudinally interviewed sample people. Therefore, on the previous SPD 3rd longitudinal file, the longitudinally interviewed sample people represented incorrectly both the living people and the dead and out-of-scope people in the SPD/SIPP universe. From the estimation standpoint, the final weights on the previous SPD 3rd longitudinal file would produce substantial over-estimation of living people. On the current SPD 3rd longitudinal file, we have corrected this error by reweighting the file and classifying these people as longitudinally interviewed up until they came out of scope.
⁴The values for the NATVTY variable in the data dictionary are found in the natvty.txt file.
⁵Note that an updated data file was placed on this server on 4/06/2004. The file was revised to correct the variable IHHKEY0X.