Background and Aims : Simulation-based training in colonoscopy is increasingly replacing the traditional apprenticeship method to avoid patient-related risk. Mentoring during simulation is necessary to provide feedback and to motivate, but expert supervisors are a scarce resource. We aimed to determine whether computerized feedback in simulated colonoscopy would improve performance, optimize time spent practicing, and optimize the pattern of training. Methods : Forty-four participants were recruited and randomized to either a feedback group (FG) or a control group (CG). Participants were allowed 2 hours of self-practice where they could practice as they saw fit on 2 different cases: one easy and one difficult. The CG practiced without feedback but the FG was given a score of progression every time they reached the cecum. All participants were tested on a different case after end of training. The primary outcome was progression score in the final case and secondary outcomes were time spent practicing and training pattern. Results : Regression analysis adjusting for sex was done due to an uneven sex distribution between groups (P = 0.026) and significantly higher performance scores by men (37.6, SD 25.9) compared with women (19.7, SD 18.7), P = 0.012. The FG outperformed the CG in the final case (FG scoring 14.4 points (95% CI, 1.2 - 27.6) more than the CG, P = 0.033) and spent more time practicing (FG practicing 25.8 minutes [95% CI, 11.6 - 39.9] more than the CG; P = 0.001). The FG practiced more on the easy case and reached the cecum 3.2 times more (95% CI, 2 - 4.5) during practice (P <0.001). Conclusions : Our findings of this study revealed that an automatic, computerized score of progression during simulated colonoscopy motivates the novices to improve performance, optimize time spent practicing, and optimize their pattern of training (Clinical trial registration number: NCT03248453).