The 1968-1999 Public Release I Individual File has been replaced with a new version, Release 2, that includes longitudinal weights for 1999 individuals. The only difference between Release 1 and Release 2 is the addition of the weight variable at the very end of each data record, following the 1999 portion of the data. No other changes were made to the file. All previously-released variables retain the same names and values as for Release 1. Get it from the PSID Data Center or download the full data and documentation in a Zip package.