Table 3.

Results of our investigation into the quality and risk of bias of the 19 included studies

Authors	Mode of randomization	RCT stopped early	Patient assignment truly randomized	Patients blinded	Data collectors blinded	Subjects accounted for at trial conclusion	Selective reporting	Groups similar at start of trial?
Wooster et al. [27]	By computer	Yes	Yes	Yes	Yes	Yes	No	NA
Maertens et al. [41]	Sealed envelope	No	No	NA	Yes and no*	Yes	No	Yes, with respect to sex, post-grad year, and number of endovascular cases assisted
Zevin et al. [52]	Sealed envelope	No	No	NA	Yes	Yes	No	Yes, with respect to a host of variables, but intervention group had significantly fewer basic bariatric surgeries performed as the primary surgeon and bariatric rotations participated in
Desender et al. [29]	Sealed envelope	No	Yes	Yes	Yes	NA	No	NA
Nilsson et al. [17]	Sealed envelope	No	No	NA	NA	Yes	No	Yes, with respect to age and experience with laparoscopic training and surgery, but not sex
Waterman et al. [46]	NA	No	No	NA	Yes	Yes	No	Yes, with respect to age, sex, post-grad year, and arthroscopies performed pre and post-intervention
Shore et al. [15]	By computer	No	No	NA	Yes	Yes	No	Yes, with respect to a host of variables (surgical experience, VR experience, musical instrument experience, etc.)
Patel et al. [16]	By computer	No	No	NA	Yes	Yes	Yes****	Groups stratified by pre-intervention human salpingectomy OSAT score, post-grad year was similar
Dunn et al. [47]	NA	No	No	NA	Yes	Yes***	No	Yes with respect to sex, post-grad year, and number of cases performed
Peltan et al. [29]	By computer	No	No	NA	Yes	Yes	No	Yes, with respect to age, sex, training track, and degree
Grover et al. [42]	Sealed envelope	No	No	NA	Yes	Yes	Yes*****	Yes, with respect to age, sex, training program, and number of colonoscopies performed and assisted
Carlsen et al. [48]	Sealed envelope	No	No	NA	Yes	Yes	No	Yes, with respect to age, sex, time in surgical employment, and prior number of performed hernia repairs
Koch et al. [49]	NA	No	No	NA	Yes	Yes	No	Yes, all subjects were at the start of their training in gastroenterology with no previous endoscopic experience
Zendejas et al. [14]	Sealed envelope	No	No	NA	Yes and no**	Yes	No	Yes, baseline TEP repair was similar, groups were similar with respect to a host of other variables (post-grad year, sex, handedness, video game experience, TEP comfort + experience)
Kessler et al. [6]	By computer	No	No	NA	No	Yes	No	Yes, with respect to sex, post-grad year and experience with LP (training, simulator experience, observations, LPs performed)
Calatayud et al. [30]	Sealed envelope	No	No	NA	Yes	Yes	Yes*****	Each surgeon served as their own control
Haycock et al. [50]	By computer	No	No	NA	Yes	Yes	No	Yes, with respect to age, sex, educational direction, sigmoidoscopies and colonoscopies witnessed/assisted/performed
Ahlberg et al. [2]	Sealed envelope	No	No	NA	Yes	Yes	No	Yes, with respect to age, sex, visuospatial assessment, working memory assessment, and laparoscopic assisting experience
Cohen et al. [51]	Random number table	No	No	NA	Yes	Yes	No	Yes, with respect to experience with gastroscopy and flexible sigmoidoscopies

*Blinded supervising surgeon was responsible for Global Rating Scale score and Examiner Checklist score, all other outcomes recorded by non-blinded investigator

**Blinded supervising surgeon was responsible for GOALS score and postoperative complications, all other outcomes recorded by non-blinded investigator group

***Paper specifies total subjects enrolled and analyzed, but not how many subjects were in control and intervention

****Fail to report any between group analysis, only reporting within group

*****Assessments are based on review of video recording of surgical procedures, but the investigators do not mention or conduct analysis of operative time, which should be readily available to them