In the Census-internal SIPP panels, a value for race is included on each wave file. Thus, there are actually as many race variables as there are waves of the survey and some changes occur across waves as a result of data collection error. Race is chosen by creating an array of variables race1-race{max number of waves} and choosing the first non-missing value. Thus race comes from the first wave in which the individual was interviewed instead of from a fixed point in the survey.

1	White
2	Black
3	Other