Not necessarily. In 1983 and again in 1993 there were sample frame experiments that are described in Appendix A. In 1983, 806 cases were from the 1970 frame (SAMPLE=3) and 793 cases from the 1980 frame (SAMPLE=6). In 1993, 817 cases were from the 1980 frame (SAMPLE=6) and 789 case from the 1990 frame (SAMPLE=8).
