Table 2.

Certainty of evidence of included studies.

Outcome	Effect	Number of studies	Certainty of the evidence (GRADE)
Resident impact on efficiency	Most (6/7) studies showed a small to moderate decrease in efficiency.	7	LOW ⊕⊕00 (due to serious risk of bias and indirectness)
Student impact on efficiency	Most (4/5) studies showed a small decrease in efficiency.	5	LOW ⊕⊕00 (due to serious risk of bias and indirectness)
Resident impact on productivity	All 3 studies showed an increase in productivity, centering around a medium effect size.	3	LOW ⊕⊕00 (due to serious risk of bias and moderate indirectness)
Student impact on productivity	Both studies showed no association with productivity.	2	LOW ⊕⊕00 (due to moderate risk of bias and severe indirectness)

GRADE, Grading of Recommendations Assessment, Development and Evaluation.