WASHINGTON, May 12 — Nearly 60 million people lack health insurance at some point in the year, the Congressional Budget Office said today, adding that official estimates fail to distinguish between people who lack coverage for a few months and those who are uninsured for a full year or more.
Members of Congress, administration officials, lobbyists and advocates often cite the Census Bureau when they declare that 41 million people have no health insurance.
But in a new report today, the budget office said the bureau's figure "overstates the number of people who are uninsured all year," while significantly understating the number who are insured for only part of the year.
The report said 57 million to 59 million people, "about a quarter of the nonelderly population," lacked insurance at some time in 1998, the most recent year for which reliable comparative figures were available.
At the same time, the budget office said, government surveys suggest that the number of people uninsured for the entire year was 21 million to 31 million, or 9 percent to 13 percent of nonelderly Americans.
The widely used figure from the Census Bureau is based on interviews conducted by the government, as part of the Current Population Survey, in March of each year. The questions about insurance are meant to identify people who were uninsured for all the prior calendar year.
But the budget office said that many people "report their insurance status as of the time of the interview, rather than for the previous calendar year as requested."
The new research confirms what some economists and health policy experts had suspected for years: that it is difficult to count the uninsured because people are continually losing and gaining coverage, and they do not always understand the questions asked in government surveys.
Douglas J. Holtz-Eakin, the new director of the Congressional Budget Office, said: "Far from being a static group, the uninsured population is constantly changing. While many people are chronically uninsured, many more are uninsured for shorter periods of time."
In writing legislation to expand coverage, Mr. Holtz-Eakin said, members of Congress must "consider the distinction between the short-term and long-term uninsured."
Lawmakers have proposed several approaches. Republicans and some Democrats want to offer tax credits to help individuals or small businesses buy private insurance. Many Democrats want to expand Medicaid, the federal-state program for low-income people, or the Children's Health Insurance Program.
Some Democrats, including Representative Richard A. Gephardt of Missouri and Senator Edward M. Kennedy of Massachusetts, want employers to provide coverage to employees, with government subsidies.
The budget office conducted its study at the request of Representative Bill Thomas, the California Republican who is the chairman of the Ways and Means Committee.
Mr. Thomas said the report offered "some good news: fewer individuals are long-term uninsured than previously thought."
But Senator Jeff Bingaman, Democrat of New Mexico, said: "The report underscores how big a crisis our country is facing. On any given day, more than 40 million Americans live with the prospect of facing financial ruin in order to pay for their health care, or going without care altogether."
One question the budget office addressed was how long people go without coverage when they are uninsured. For some, the experience is relatively brief. But others go more than two years without insurance.
The office focused on people who became uninsured from mid-1996 to mid-1997 and tracked them for several years. It found that 45 percent were uninsured for four months or less, 26 percent were uninsured for 5 to 12 months, and 13 percent lacked coverage for 13 to 24 months, while 16 percent were uninsured more than two years.
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