To aid state and local policymakers, program planners, and community advocates, UCLA Center for Health Policy Research staff created estimates of the percentage of the population lacking health insurance in small geographic areas of California.

Health insurance coverage among nonelderly persons varied widely across assembly districts, from 10% to 44%. The utility of local-level estimates was most apparent when the variations in subcounty uninsured rates in Los Angeles County (19%-44%) were examined. 

The study found that stable and useful estimates of health insurance rates for small areas such as legislative districts can be created through use of multiple sources of publicly available data.