Uninsured children: how we count matters.

BACKGROUND Because children uninsured for less than a full year are often reported as insured, they receive less attention in health policy debates than do the full-year uninsured and are underrecognized as potential users of public insurance programs. OBJECTIVE The purpose of this study is to assess the impact on estimates of how many US children are uninsured when alternatives to the full-year uninsured definition are used. METHODS Monthly health insurance coverage data collected from children through age 18 in the 1999 Medical Expenditure Panel Survey were analyzed to estimate prevalence of health insurance gaps among children in terms of the size of part-year and full-year uninsured child population, duration of uninsured gaps, and aggregate uninsured spells. RESULTS Although 6.6 million ([M] 8.4%) children in the United States were uninsured throughout 1999, an additional 11.4M (14.4%) were uninsured for part of the year. Part-year uninsured gaps accounted for 41.7% of a total of 130M months of missing coverage experienced by all children. CONCLUSIONS Different definitions and measures of who are uninsured can project radically different pictures of the magnitude of the problem. As this study shows, including the part-year uninsured more than doubled the estimated uninsured child population for 1999, and increased the estimated aggregate uninsured months by 71%. As potential users of public coverage, children who have no insurance for part of the year should be included when evaluating challenges to and accomplishments by the State Children's Health Insurance Program and other public programs. Their significant numbers and the potential burden they place on the health care delivery system argue for them to be counted and for the causes and consequences of short-term uninsured spells to be better understood.