HHS collects sampled data from states, which permits it to determine the size and composition of cases by states. The data sources are the National Integrated Quality Control System (QC) prior to 1997 and the Emergency TANF Data Report starting in 1997. Both data sources rely on a sample of records submitted by states.
The data are limited in two ways. First, sample sizes are generally not large enough to examine basic demographic information of the child-only caseload by state. Second, the reasons the cases are child-only are often unknown (13 percent of the cases in 1997 were unknown). To supplement these data, HHS contracted with TLG to collect more detailed information from case files in three counties and, to the extent possible, state administrative data.