Background: Reflection on professional experience is increasingly accepted as a critical attribute for health care practice; however, evidence that it has a positive impact on performance remains scarce. This study investigated whether, after allowing for the effects of knowledge and consultation skills, reflection had an independent effect on students' ability to solve problem cases. Methods: Data was collected from 362 undergraduate medical students at Ghent University solving video cases and reflected on the experience of doing so. For knowledge and consultation skills results on a progress test and a course teaching consultation skills were used respectively. Stepwise multiple linear regression analysis was used to test the relationship between the quality of case-solving (dependent variable) and reflection skills, knowledge, and consultation skills (dependent variables). Results: Only students with data on all variables available (n = 270) were included for analysis. The model was significant (Anova F(3,269) = 11.00, p <0.001, adjusted R square 0.10) with all variables significantly contributing. Conclusion: Medical students' reflection had a small but significant effect on case-solving, which supports reflection as an attribute for performance. These findings suggest that it would be worthwhile testing the effect of reflection skills training on clinical competence.