AbstractTraditionally, professional expertise has been judged by length of experience, reputation, and perceivedmastery of knowledge and skill. Unfortunately, recent research demonstrates only a weak relationshipbetween these indicators of expertise and actual, observed performance. In fact, observed performancedoes not necessarily correlate with greater professional experience. Expert performance can, however,be traced to active engagement in deliberate practice (DP), where training (often designed and arrangedby their teachers and coaches) is focused on improving particular tasks. DP also involves the provisionof immediate feedback, time for problem-solving and evaluation, and opportunities for repeated performance to refine behavior. In this article, we draw upon the principles of DP established in otherdomains, such as chess, music, typing, and sports to provide insight into developing expert performancein medicine