Purpose/Hypothesis: Recent research on the APTA Physical Therapist Student Evaluation of Clinical Experience and Clinical Instruction provides evidence that the PT profession is without a reliable and valid tool to assess clinical instructor (CI) performance. To fill the profession’s void of a trustworthy outcome measure that could be used to provide formative and summative feedback for clinical instructor performance improvement, a physical therapy education program developed a tool that allows for brief student and CI assessment of self and each other at regular intervals during clinical education experiences (CEE). Student and CI discussion of this performance assessment data provide clarification of CI growth opportunities. Site coordinator and director of clinical education real-time access to each completed assessment allows for formative mentoring of CIs. The purpose of this presentation is to describe the results of the pilot study that quantitatively assessed the construct validity of this tool and qualitatively explored the CI experience of being mentored via use of the tool at regular points throughout a CEE. Number of Subjects: 144 Materials and Methods: Students and their CIs completed the Student and Clinical Instructor Performance Assessment Instrument (SCIPAI) electronically every 1-2 weeks throughout CEE, using a rating scale and supporting comments to describe student and CI performance in this mixed-methods study. With the PT profession having no referent tool available on which to base concurrent validity, the researchers assessed construct validity of SCIPAI CI performance measures by comparing initial and final SCIPAI CI performance scores. The researchers then qualitatively analyzed student and CI comments supporting SCIPAI ratings to identify themes characterizing CI performance throughout each clinical. Results: Significant differences between initial and final measures of CI performance during CEE (p<.05) support SCIPAI construct validity. Qualitative analyses of comments on CI performance highlight themes of CI attention to frequency, timing, and nature of feedback and CI modification of nature of supervision throughout CEE. Conclusions: Regular assessment of student and CI performance throughout CEE using the SCIPAI provides multiple opportunities for formative feedback via real-time data to students, CIs, DCEs, and SCCEs. Quantitative analysis of pilot study data supports the SCIPAI as demonstrating construct validity. Qualitative analyses of comments supporting ratings of CI performance using the SCIPAI highlight themes of CI growth in providing supervision and feedback. Clinical Relevance: For a profession lacking valid and reliable measures of CI performance, this tool demonstrates potential for CI performance assessment. Additional research is warranted to further evaluate the tool’s validity and reliability and to explore how all CE stakeholders can use the SCIPAI to inform best practices in clinical instruction.