In particular:

• For 1969-1981, persons age 6-16 years may appear in the categories "going to school" (30) and "something else" (50), while for 1982-1996, only persons age 18+ years will appear in these categories.

• For 1969-1981, persons age 17 years may appear in the category "Working" (10), while for 1982-1996, only persons age 18+ years will appear in this category.

• In the 1969-1981 survey, there was a specific set of questions for males and females age 6-16 years, while this set of questions was absent in the 1982-1996 survey.

• In the 1969-1981 survey, there was a specific set of questions for males or females, age 45+ years, who were retired. This set of questions is absent in the 1982-1996 survey.

• As noted in the previous bullet point, in 1969, there was a specific set of questions for males or females, age 45+ years, who were retired. However, the 1969 public access files do not contain the detailed information about retired persons present in 1970-1981. The 1969 information about males or females, age 45+ years, who were retired, is fully contained in the category "Retired (45+ years)" (40). Researchers can, for 1970-1981, combine "Retired - Health (45+ years)" (41) and "Retired - Other (45+ years)" (42), into a single category fully comparable with 1969's "Retired - Health (45+ years)" (40).

• There were no follow-up questions about retirement for 1982-1996, and all persons who were neither working nor keeping house nor going to school were grouped together under the heading "something else." To achieve comparability before and after 1982, researchers must similarly combine retirees (codes 40-42) with those "doing something else" (code 50) in the earlier years.

• In 1969-1981, the skip patterns of the questions associated with MAJACT excluded males from answering questions about "keeping house." However, in 1982-1996, it was possible for males to answer that their major activity in the past 12 months was keeping house. Thus, the category "keeping house" (20) may, in 1982-1996, include both males and females, while "keeping house" (21) for 1969-1981 includes only females.

Prior to 1994, the March Current Population Survey included similarly phrased, sex-specific questions on major activity during the previous week. The Bureau of Labor Statistics concluded that such phrasing--which presumes that men's normative activity is paid employment and that women's normative activity is keeping house--resulted in underreporting of paid employment by women.