When one mentions the word “professional,” images come to mind of lone doctors or lawyers pursuing their practice as they see it. Romantic as this image may be, in the 21st century professionals typically practice in an organizational setting (Mumford, Scott, Gaddis, & Strange, 2002). In these settings, leadership of the organization is a critical influence on the productivity of professionals (West, Borrill, Dawson, Brodbeck, Shapiro, & Haward, 2003). This rather straightforward observation has an important, albeit often overlooked, implication. To ensure the productivity of professionals, one must also ensure that they are led effectively.

Over the course of the last century the study of leader effectiveness has come to preoccupy, if not obsess, the social sciences (Bass, in press; Yukl, 2002). Broadly speaking, this research has given rise to two major approaches that have sought to enhance performance of those who lead other professionals. More specifically, one might 1) select to employ effective leaders or 2) seek to train or develop current employees into effective leaders (Bray & Howard, 1988; Day, 2000). These two approaches implicitly assume that differences in leadership performance can be measured objectively in terms of the output of the group or system. Over the years, a host of techniques have been proposed for leader development and leader assessment – techniques ranging from assessment centers (Byham & Thornton, 1986) to classroom instruction (Fiedler, 1996) to real-world experience (McCauley, Ruderman, Ohlott, & Morrow, 1994).