title: Changes in the incidence and duration of periods without insurance.
abstract: BACKGROUND
  Policymakers have recently proposed ways of providing health care coverage for an increased number of uninsured persons. However, there are few data that show how the incidence and duration of periods in which persons do not have insurance have changed over time.
  
  
  METHODS
  We used two data sets from the Survey of Income and Program Participation of the U.S. Census Bureau: one that covered the period from 1983 through 1986 (25,946 persons), and another that covered the period from 2001 through 2004 (40,282 persons). For each set of years, we estimated the probability that a person would be uninsured for some period of time and the probability that a person would subsequently obtain private or public insurance. We also estimated the probabilities that persons in various demographic groups would become uninsured over the course of a year and would remain uninsured for various amounts of time.
  
  
  RESULTS
  The percentage of the population that lost insurance in a 12-month period increased from 19.8% in 1983-1986 to 21.8% in 2001-2004 (P=0.04). The percentage that was uninsured for a period of time increased markedly among persons with the lowest educational level and predominantly represented loss of private coverage. The percentage of new uninsured periods that ended within 24 months increased from 73.8% to 79.7% between the two study periods (P<0.001); increases were seen in all age groups and among persons of all educational levels. Transition from no insurance to private insurance decreased from 65.2% to 59.2% (P<0.001). Transition from no insurance to public insurance increased from 8.7% to 20.4% (P<0.001).
  
  
  CONCLUSIONS
  As compared with the years from 1983 through 1986, from 2001 through 2004, more people, particularly those with the lowest educational level, had periods in which they were not insured. The periods without insurance were shorter in 2001-2004 than they were in 1983-1986, since an increase in transitions to public coverage offset a reduction in transitions to private coverage. Our results portend difficulties if private coverage continues to decline and is not offset by further expansions of public insurance.
authors.affiliation: Department of Economics, Harvard University, and the National Bureau of Economic Research, Cambridge, MA 02138, USA. dcutler@harvard.edu
authors.forename: David M
authors.initials: DM
authors.lastname: Cutler
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Gelber
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003625:Data Collection; D004522:Educational Status; D005260:Female; D006801:Humans; D019458:Insurance Coverage / Q000706:statistics & numerical data / Q000639:trends*; D007348:Insurance, Health / Q000706:statistics & numerical data / Q000639:trends*; D008297:Male; D017057:Medically Uninsured / Q000706:statistics & numerical data*; D008875:Middle Aged; D017149:Private Sector / Q000706:statistics & numerical data / Q000639:trends; D016016:Proportional Hazards Models; D017150:Public Sector / Q000706:statistics & numerical data / Q000639:trends; D014481:United States; D055815:Young Adult