This dissertation combines three complementary studies that focused on the assessment and determined the quality of the written performance feedback practices and processes used by university supervisors with special education teacher candidates (SETCs) to improve their practice during field experiences. In the first study, a systematic review of the empirical research was conducted to determine the critical components of effective written performance feedback interventions. We used empirical research from the systematic literature review in the second study and analyzed each intervention's method section. We then combined those practices into an initial measurement tool to assess the quality of written feedback practices and processes. We conducted cognitive interviews and expert reviews to refine the initial version of the Quality of Written Performance Feedback for Improvement of Practices and Process (QWIPP) tool. In the third study, we used data from a larger IES grant-funded project to investigate three essential things: (a) the quality of written feedback practices and processes of university supervisors, (b) whether there is a significant difference in their QWIPP scores based on the type of form used by the supervisor, and (c) the overall reliability of the QWIPP. The results showed a significant range of practices and processes used by university supervisors, no significant difference in QWIPP scores based on form type, and that the QWIPP has strong inter-rater reliability scores (i.e., 92%) and internal reliability for a new measurement tool (i.e., Cronbach's [alpha] = 0.73).Synthetization of findings across studies include critical recommendations that include: (a) designing training for university supervisors to ensure they are using best practices when they develop their written feedback; (b) using best-written performance feedback practices is a simple solution that has utility and flexibility to be used across multiple facets to address the special education teacher shortage; (c) identifying university supervisors practices impact candidates, and they should not rely on their observation protocols to give high quality written feedback to their teacher candidates; (d) there is value-added to institutes of higher education providing teacher preparation by focusing on the best practices in written performance feedback. This dissertation thoroughly examines the best practices and processes of written performance feedback that informs teacher preparation practices and future impact on the field and policymaking to further enhance educational outcomes for students with disabilities by focusing on the implementation fidelity of the practice of SETCs. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]