The purpose of this guidebook is to enable states and researchers to conduct their own studies on the dynamics of child care subsidy use. To accomplish this goal, this guidebook describes the methodology developed through a five-state study on this topic. Although there are various ways one could approach a study on child care subsidy use, replicating the same methodology will enable states to compare their findings with those of other states. These comparisons increase the usefulness of the states' findings. Further, by sharing states' findings, we will begin to create a national picture of the dynamics of child care subsidy use.