IntroductionThe clinical teaching unit (CTU) has emerged as a near-ubiquitous model of clinical education across Canadian and international medical schools since it was first proposed over 50 years ago. However, while healthcare has changed dramatically over this period, the CTU model has remained largely unchanged. We thus aimed to systematically review principles of CTU design that contribute to improved outcomes in clinical education and health service delivery.Methods and analysisWe will perform a realist systematic review in accordance with the Realist And Meta-narrative Evidence Syntheses: Evolving Standards (RAMESES) II protocol for realist reviews. Databases, including MEDLINE, Embase, Cochrane Database of Systematic Reviews and Cumulative Index of Nursing and Allied Health Literature (CINAHL), were searched to find primary research articles published from 1993 to 2019 involving CTUs or other teaching wards, and outcomes related to either trainee education or health service delivery. Two reviewers will independently screen studies in a two-stage process. Retrieved titles and/or abstracts of studies will be screened in the first stage, with full texts reviewed in the second stage. Selected articles meeting inclusion criteria will undergo data abstraction using a standardised, pre-piloted form for assessment of study quality and knowledge synthesis.Ethics and disseminationThis review will generate higher quality evidence on the design of CTUs as a model for both clinical education and health service delivery. In addition, further knowledge translation efforts may be necessary to ensure that known best practices in CTU design become common practice.

Background:The clinical teaching unit is a widespread clinical training model that requires reform to prepare phys icians for practice in the 21st century. In this systematic review, we aimed to identify evidencebased practices in internal medicine clinical teaching units that contribute to improved clinical education and health care delivery.