Comparing income-shares and percentage-of-income child support guidelines

Child support guidelines are one of the most explicit, and consequential, public articulations of parents' obligations to their biological children. States must weigh a variety of policy tradeoffs, including issues of equity, transparency, and simplicity. Many states are shifting to “income-shares” guidelines models from “percentage-of-income” models, citing a perceived increase in equity and flexibility. Given additional complexities in implementing the income-shares model, we ask how often, and for whom, alternative guidelines yield substantially different child support orders. We use state administrative data on matched pairs of divorcing parents to simulate expected order amounts for each type of guideline. We find that, despite substantial differences in the information required to implement alternative models, for most families, adopting a different model would result in only modest changes in the amount of child support due. However, in some instances a different model would result in large changes, particularly for relatively low-income fathers.