The Children's Health Insurance Program (CHIP) participation data are obtained from state counts gathered from a web page of the Centers for Medicare and Medicaid Services (CMS). We use these state counts because data are not available at the county level for most of the counties. We make several approximations to the CHIP data to make them usable with our age/sex groupings; sex, age and the average number of participants in the third fiscal quarter are approximated. In each case, the Medicaid Statistical Information System (MSIS) data guided our decisions. We then use the Medicaid data to determine a ratio for allocating the adjusted CHIP numbers to counties by sex.
We combine the CMS MSIS and CHIP participation data together into one variable for use in our models. For the 2000 age model, adjusted CHIP data were not included.