Rater-mediated assessments require the evaluation of the accuracy and consistency of the inferences made by the raters to ensure the validity of score interpretations and uses. Modeling rater response processes allows for a better understanding of how raters map their representations of the examinee performance to their representation of the scoring criteria. Validity of score meaning is affected by the accuracy of raters' representations of examinee performance and the scoring criteria, and the accuracy of the mapping process. Methodological advances and applications that model rater response processes, rater accuracy, and rater consistency inform the design, scoring, interpretations, and uses of rater-mediated assessments.