There have been many new developments in the broad fields of epidemiology, health services research (HSR), and outcomes research during the past year, many more than can be discussed in detail in this review. We selected articles published since the last article in this series (1 H.M. Krumholz and F.A. Masoudi, The year in epidemiology, health services research, and outcomes research, J Am Coll Cardiol 50 (2007), pp. 2253–2262.1), covering roughly the period April 2007 through March 2008, that examined important issues or advanced research methods in the field.