The KCDC's Harmonized Variable version of the CPS data is designed to "link" variables from 1976 to the present where possible. Harmonized variables in the dataset can be linked either between the 1976 and the 1989 versions of the CPS, the 1989 and the 1994 versions of the CPS, or across all three versions. The data are recoded in some cases in order to ensure consistency of measurement over time.
Variables are named in the following convention:
VARNAME_ab -> a variable linked from the 1976 version of the CPS to the 1989 version of the CPS
VARNAME_bc -> a variable linked from the 1989 version of the CPS to the 1994 version of the CPS
VARNAME_abc -> a variable linked across all three versions of the CPS.