Details about the characteristics of insurance plans (such as HI1EMP) reflect plans for any family member in the household. In order to determine if the person (rather than someone else in the family) was covered by this plan, analysts should use the variable HI1PCOV (Health Insurance Plan 1: Person's Coverage Status), which indicates whether the person was covered by the plan.

Information was collected on up to five private plans in most years (and on up to six plans in 1983).

Thus, information about whether the person had private insurance that was currently carried through an employer or union may appear in multiple variables: HI1EMP, HI2EMP, HI3EMP, HI4EMP, and HI5EMP. Likewise, the complementary variables HI1PCOV, HI2PCOV, HI3PCOV, HI4PCOV, and HI5PCOV indicate coverage status for the individual under each plan.

For 1982 to 1989, plans that paid only for accidents or for only one type of service were not considered to constitute private health insurance, but plans that paid "extra cash" for hospital stays were considered to be health insurance.

One key difference was that prior to 1989, interviewers did not explicitly instruct respondents to exclude single service plans when reporting insurance coverage. In contrast, in 1989, the Field Representative's Manuals specifically indicated insurance had to be a comprehensive plan and not a single service plan and to exclude plans that pay for only one service.

The 1989 survey was the first year which distinguished single service plans from comprehensive insurance, and was the first year information on such plans was collected. The 1989 Manual noted, "There are many health care plans now available that pay only for a specific health care service, such as prescriptions, cancer treatment, or eye care. These plans are generally offered in addition to the usual comprehensive coverage."