Purpose Clinical teaching's importance in the medical curriculum has led to increased interest in its evaluation. Instruments for evaluating clinical teaching must be theory based, reliable, and valid. The Maastricht Clinical Teaching Questionnaire (MCTQ), based on the theoretical constructs of cognitive apprenticeship, elicits evaluations of individual clinical teachers' performance at the workplace. The authors investigated its construct validity and reliability, and they used the underlying factors to test a causal model representing effective clinical teaching. Method Between March 2007 and December 2008, the authors asked students who had completed clerkship rotations in different departments of two teaching hospitals to use the MCTQ to evaluate their clinical teachers. To establish construct validity, the authors performed a confirmatory factor analysis of the evaluation data, and they estimated reliability by calculating the generalizability coefficient and standard error measurement. Finally, to test a model of the factors, they fitted a structural linear model to the data. Results Confirmatory factor analysis yielded a five-factor model which fit the data well. Generalizability studies indicated that 7 to 10 student ratings can produce reliable ratings of individual teachers. The hypothesized structural linear model underlined the central roles played by modeling and coaching (mediated by articulation). Conclusions The MCTQ is a valid and reliable evaluation instrument, thereby demonstrating the usefulness of the cognitive apprenticeship concept for clinical teaching during clerkships. Furthermore, a valuable model of clinical teaching emerged, highlighting modeling, coaching, and stimulating students' articulation and exploration as crucial to effective teaching at the clinical workplace.