"Substantiation" denotes child welfare system (CWS) services' official decision about the validity of maltreatment allegations. This decision is an important one, with implications for how much a child and family are involved with the CWS, what services they receive, and how child maltreatment is counted in state statistics. Despite the importance of the substantiation decision, there are few data on how caseworker judgments influence the substantiation process. This research brief examines the relationship of caseworker judgments to the substantiation decision, using data from the National Survey of Child and Adolescent Well-Being (NSCAW). It examines (1) how the degree of perceived harm to the child relates to the decision; (2) the importance of the caseworker's perception of the severity of future risk to the child; and (3) how the caseworker's judgment about the strength of the evidence relates to the decision. (Contains 4 figures and 10 notes.)