This Study Snapshot highlights key findings from a larger study examining the validity and reliability of the Kansas Clinical Assessment Tool (K-CAT), a newly developed tool for assessing the performance of teacher candidates. The study team used interviews with cooperating teachers, content experts' ratings of the alignment of the K-CAT to professional teaching standards, K-CAT scores, and scores from the Praxis Principles of Learning and Teaching and the Kansas Performance Teaching Portfolio to assess the face validity, content validity, convergent validity, and criterion-related validity of the K-CAT, as well as internal consistency as a measure of the instrument's reliability. The study found that cooperating teachers reported that the K-CAT accurately represented existing teaching performance standards (face validity). Two skilled raters found that the content of the K-CAT was mostly aligned to existing teaching performance standards (content validity). In addition, K-CAT scores for the same teacher candidate, provided by cooperating teachers and supervising faculty, were positively related (convergent validity). [For the full report, see ED613622. For the Study Brief, see ED613624. For the appendixes, see ED613625.]