Assessing clinical reasoning: moving from in vitro to in vivo.

The last century saw dramatic changes in clinical practice and medical education and the concomitant rise in high-stakes, psychometrically-based examinations of medical knowledge. Higher scores on these high-stakes "in-vitro" examinations are modestly associated with better performance in clinical practice and provide a meaningful degree of assurance to the public about physicians' competency in medical knowledge. However, results on such examinations explain only a small fraction of the wide variation currently seen in clinical practice and diagnostic errors remain a serious and vexing problem for patients and the healthcare system despite decades of high-stakes examinations. In this commentary we explore some of the limitations of high-stakes examinations in assessing clinical reasoning and propose utilizing situated cognition theory to guide research and development of innovative modes of "in-vivo" assessments that can be used in longitudinally and continuously in clinical practice.