There were 13,949,218 child support-eligible families in the United States in 1997. A child support-eligible family is defined as a custodial parent with an own child under age twenty-one living in the household whose other parent is living but absent from the household. A majority of the child support-eligible population receives services through the IV-D program. This analysis found that 8.4 million families, or 60 percent of the 13.9 million child support-eligible parents, participated in the IV-D system. Table 1 provides an overview of all of the family variables analyzed in this report, shown for the entire child support-eligible population. Beginning with Table 2, all subsequent tables identify these characteristics within the IV-D and non IV-D populations.