The risk assessment developed from this study classified sampled clients so that outcome rates increased with each increase in the risk classification; for example, among sample clients classified as low risk, 5.2 percent had a subsequent investigation by Adult Protective Services (APS) for either maltreatment or self-neglect during the follow-up period, compared to 9.4 percent of moderate-risk clients and 23.9 percent of high-risk clients. The client risk groups experienced significantly different future rates of abuse or neglect; the proportion of high-risk clients investigated for self-neglect or maltreatment in the 6 months following the sample APS investigation was more than four times that of the low-risk group. The underlying logic of the risk assessment and subsequent classification is that the most effective way to reduce adult and elderly maltreatment is to identify high-risk clients, prioritize them for intensive agency intervention, and deliver effective services appropriate to their needs. The study sample consisted of 763 unique clients investigated for allegations of self-neglect or maltreatment between March 1 and September 30, 2009. Individual and case characteristics observed at the time of the sample investigation included the type of maltreatment alleged and confirmed; demographic data on clients and perpetrators; psychosocial characteristics and health information about the individual and, if one was present, the primary support person and information describing whether services were arranged or refused. Data describing subsequent APS outcomes were observed for each client during a standardized follow-up period of 6 months after the sample report. 10 tables and 30 references