The systems approach to analyzing adverse events emphasizes how active errors (those made by individuals) and latent errors (underlying system flaws) contribute to preventable harm. Adverse events in ambulatory care may arise from an especially complex array of latent errors. This paper explores the role of time management problems, which the authors term "tempos," as a contributor to errors in ambulatory care. Through a review of closed malpractice claims, the authors identify 5 tempos that can affect the risk of an adverse event: disease tempo (the expected disease course), patient tempo (timing of complaints and adherence to recommendations), office tempo (including the availability of clinicians and test results), system tempo (such as access to specialists or emergency services), and access to knowledge. The role of these tempos in precipitating diagnostic errors and communication errors is discussed through analysis of the patterns of errors in malpractice claims. A preventable adverse event caused by misunderstanding of disease tempo is discussed in this AHRQ WebM&M commentary.