A Rater Evaluation Survey (RES) is a tool used to assess the performance, consistency, or reliability of raters who conduct clinical assessments in a trial.
Rater consistency is especially important in studies with subjective endpoints such as psychiatric scales, neurologic assessments, or clinician-rated symptom measures. RES tools can identify training needs, drift over time, or site-to-site variability that could bias study results. Documented rater evaluation supports endpoint quality by demonstrating that assessments are performed competently and consistently. Strong rater oversight reduces measurement error and improves the interpretability of efficacy outcomes.