The Congressional Budget Office (CBO) has refined the often-quoted estimate that about 40 million Americans lack health insurance.
CBO says the estimate "overstates the number of people who are uninsured all year." The agency believes instead that between 21 million and 31 million people were uninsured for all of 1998, the last year for which reliable comparative data are available. (See graph, below.) Since 1998, analysts say, the number who are uninsured all year probably has not changed substantially. Also, the uninsured population is fluid, with many people gaining and losing coverage.
A CBO issue summary says that education level and family income are closely tied to the likelihood of being uninsured. In contrast, the likelihood of being uninsured did not vary greatly by self-reported health status in 1998.
The uninsured population is constantly changing, and the duration of uninsured spells varies with demographic characteristics such as education, race/ethnicity, and income. About 30% of nonelderly Americans who become uninsured in a given year remain so for more than 12 months, while nearly half regain coverage within four months.
The congressional analysts say that policies aimed at increasing insurance coverage are most likely to be effective if they consider the distinction between the short-term and long-term uninsured. "For people with short uninsured spells, policies might have the goal of filling a temporary gap in coverage of preventing a gap from occurring," the report says. "For people with longer people without insurance, policies might seek to provide or facilitate an ongoing source of coverage."