What’s the best predictor of success in residency and beyond? The answer is critical thinking, according to a recent study. When researchers analyzed four different sets of data on a group of Canadian medical residents—including the results on a family medicine certification exam, MCAT scores, the resident’s Canadian Residency Matching Service (CaRMS) file and the results on a critical thinking test (known as the California Critical Thinking Skills Test or CCTST)—it turned out that it was the results on the CCTST that were the best harbingers of a successful residency outcome.  According to the researchers, while many residency programs use a variety of criteria and tools to choose students, “the results of this study suggest that [critical thinking test] may be useful as a tool for improving resident selection.”