Many people are concerned about the growing number of Americans who lack health insurance. This report uses data from the Survey of Income and Program Participation (SIPP) to examine this issue. It focuses primarily on the extent to which people were covered by health insurance over a 36-month period beginning in early 1993. The source of this information is the first nine waves of the 1993 panel of the SIPP.

During each SIPP interview, information is collected on health insurance coverage (along with other information on income and labor force and program participation) for each month in the 4–month reference period. It is therefore possible to classify people by the number of months over the 36-month period that they were covered by one or more types of health insurance. It is also possible to measure the number of months continuously spent without insurance coverage, that is, spells of noncoverage.

Health insurance in this report refers to the following types of coverage: (1) employment-based insurance, (2) other privately purchased health insurance, (3) Medicare, (4) Medicaid, and (5) military health care.