by Kaiser Family Foundation show that only 2.3 million children were enrolled in June 2000 (Smith and Rousseau, 2001).
Bilheimer reported on data from Oregon and Kansas that illustrate the high levels of volatility in insurance status for the SCHIP-eligible population. The Oregon data indicate that half of the SCHIP enrollees came directly from Medicaid and almost half of the SCHIP disenrollees went back to Medicaid. Kansas reported that three-quarters of their first-time SCHIP enrollees had been in Medicaid at some point prior to their enrollment in SCHIP and that more than one-third of their SCHIP disenrollees went directly into Medicaid. Bilheimer argued that because of the many transitions, the point-in-time number is much more meaningful than the ever-enrolled number.
Administrative data may not provide a completely accurate picture of SCHIP enrollment due to inadequacies in some state’s administrative data systems. Lack of a consistent identifier for a child over time may make it difficult to distinguish whether the same child is enrolling and reenrolling, or whether two distinct children are enrolled. Creating identifiers that track all of the children in a family is also important. This was complicated, however, by the fact that, prior to June 25, 2001, states were prohibited from asking SCHIP enrollees for their Social Security numbers. Some states that have chosen to implement SCHIP by expanding Medicaid have incorporated the reports on their SCHIP enrollees into their preexisting Medicaid data systems. As Bilheimer pointed out, the latter were primarily designed to track enrollment and pay medical bills and are often ill suited for use as a management tool. Although SCHIP provides the opportunity to put in place data systems better suited for management purposes, these systems still need to interface with the Medicaid data systems, given the high rate of transition between the two programs.
Given the difficulties in relating administrative data to an appropriate estimate of the number of eligible children, some sample surveys estimate both the number eligible for participation in SCHIP and the number enrolled. For example, Dubay reported that the National Survey of America’s Families oversamples low-income populations, thus permitting national estimates as well as more disaggregated estimates of enrollment in 13 states. Among the 13 states, the estimates of percentage of eligible children enrolled in Medicaid in 1999 ranged from 58.4 percent in Texas to 92.7 percent in Massachusetts. Enrollment in SCHIP ranged from a low of 34.7 percent of eligible children in Florida to 88.1 percent in Massachusetts.