Volume 42 | Number 6p2 | December 2007

Abstract List

Genevieve Kenney, James Marton Ph.D., Joshua McFeeters, Julia Costich


To assess whether new premiums in SCHIP affect rates of disenrollment and reenrollment in SCHIP and whether they have spillover enrollment effects on Medicaid.

Data Source

We used SCHIP administrative enrollment data from Arizona and Kentucky. The enrollment data covered July 2001 to December 2005 in Arizona and November 2001 to August 2004 in Kentucky.

Study Design

We used administrative data from two states, Arizona and Kentucky, which introduced new premiums for certain income categories in their SCHIP programs in 2004 and 2003, respectively. We used multivariate hazard models to study rates of disenrollment and re‐enrollment for the recipients who had been enrolled in the categories of SCHIP in which the new premiums were implemented. Competing hazard models were used to determine if recipients leaving SCHIP following the introduction of the premium were obtaining other public coverage or exiting public insurance entirely at higher rates. We also used time‐series models to measure the effect of premiums on changes in caseloads in premium‐paying SCHIP and other categories of public coverage and we assessed the budgetary implications of imposing premiums.

Principal Findings

In both states, the new premiums increased the rate of disenrollment and decreased the rate of re‐enrollment in premium‐paying SCHIP among the children who were enrolled in those categories before the premiums were implemented. The competing hazard models indicated that almost all of the increased disenrollment is caused by recipients leaving public insurance entirely. The time‐series models indicated that the new premium reduced caseloads in premium‐paying SCHIP, but that it might have increased caseloads for other types of public coverage. The amount of premiums collected net of the costs associated with administering premiums is small in both states. Estimating the full budgetary effects with certainty was not possible given the imprecision of the key time‐series estimates.


These results suggest that the new premium reduced enrollment in the premium‐paying group by 18 percent (over 3,000 children) in Kentucky and by 5 percent (over 1,000 children) in Arizona, with some of these children apparently leaving public coverage altogether. While most children enrolled in these categories did not appear to be directly affected by the imposition of $10–$20 monthly premiums, the premiums may have caused some children to go without health insurance coverage, which in turn could have adverse effects on their access to care. Imposing nominal premiums may reduce state spending, but projected savings appear to be small relative to total state SCHIP spending and resulting increases in enrollment in other public programs and in uninsurance rates could offset those savings.