This research brief addresses the need for an aggregate picture of the methods, measures, and analytic strategies being used in QRIS validation studies by summarizing the measures that researchers are currently using or plan to use. To gather information on current QRIS validation study measures, Child Trends compiled data used to inform the Quality Initiatives Research and Evaluation Consortium (INQUIRE) validation workgroup, and reviewed published reports and research plans for RTT-ELC validation studies. A total of 19 QRIS validation studies were examined. All 19 of the validation studies are conducting analyses to assess how well items on the rating tool are working; 18 of the studies are assessing whether program quality ratings are different in meaningful ways; and, 16 studies are assessing whether quality ratings are related to measures of children’s development. The Environment Rating Scales (ERS) and the Classroom Assessment Scoring System (CLASS) are the most commonly used observation tools in validation studies; in contrast, the set of child development measures used in validation studies varied across state. The brief also summarizes the structural quality indicators collected in the studies, covariates used in validation analyses, and some of the challenges that have been encountered in choosing a school readiness battery. The research brief was developed to inform discussions in the INQUIRE validation subgroup meetings but is being shared widely to facilitate a common understanding among QRIS stakeholders about QRIS validation studies.