Medicaid and CHIP retention among children in 12 states.

Objective: Though stable insurance is important to support optimal child health, the reproducibility of metrics to assess child health insurance retention at the state and county level has not been examined. We sought to determine reproducibility of public insurance retention rates for children using 3 different metrics at the state and county level.

Methods: Public health insurance retention for children was assessed using 3 different metrics calculated from 2006-2009 Medicaid Analytic Extract data from 12 selected states. The metrics were: 1) Duration: a prospective metric that quantifies the number of newly enrolled children continuously enrolled in public insurance 6, 12, and 18 months after initial enrollment during a selected period; (2) Infant Duration: assesses Duration only among infants born during a selected period; (3) Coverage: a prospective metric that quantifies the average percentage of time a selected population is enrolled over an 18-month interval. Reproducibility of the metrics was assessed using a range of sample sizes with resampling and determining changes in relative rankings of states/counties by retention rate.

Results: All 3 metrics demonstrated reproducible estimates at the state level with sample sizes of 2000, 5000, and 10,000. Reproducibility of relative rankings for child health insurance retention of counties within states were sensitive to county child population size and the amount of variability in retention rates within the county and at the state level.

Conclusions: As health care reform unfolds, the complete set of these 3 reproducible metrics can be used to evaluate multipronged and multilevel strategies to retain eligible children in public health insurance.