Hallinger and Heck (1996, 1998) resolve a perennial question over whether schools—or, more important, students—need principals if the sole purpose of schooling is better performance on achievement tests. In fact,. Hallinger and Heck's work potentially lays to rest the overly simplistic question of whether principals directly influence students' test scores. On the other hand, their work supports a move to more complexity in the conceptualization of instructional leadership as well as more sophistication in research design, measurement, and analysis techniques to answer the question of what instructional leaders do. Finally, Hallinger and Heck offer important evidence that the question ought to ask not only what instructional leaders do but also how they interact with school contexts and in what ways they react strategically to their environments to promote learning.