Despite the rapid growth of Medicaid home care services, no uniform system for measuring and improving the quality of these services has been implemented on a large scale. The Personal and Skilled Care Outcomes (PESO) data set was developed to provide non-Medicare-certified home care agencies with a data set to support the systematic assessment and improvement of patient outcomes. This article describes the key features of the data set and outlines ways that a PESO-based outcome-based quality improvement process can be refined to accommodate the unique mix of services provided by home care agencies serving the Medicaid and private-pay populations.