Background: This report continues in the lineage of reviews of research in educational leadership and management by examining methodological approaches used by doctoral researchers in studying principal instructional leadership. Research Design: The article reviews the full set of 130 doctoral dissertations completed over the past three decades that used the Principal Instructional Management Rating Scale (PIMRS). The report analyzes trends in the research foci, conceptual models, research designs, and statistical methods employed in these studies. Findings: The study finds that interest in instructional leadership among scholars and practitioners remained strong throughout the period of the review, the PIMRS has proven a reliable and valid data collection tool, and the use of research methodology has improved in several specific areas. Nonetheless, the results also suggest that the conceptual frameworks and methodologies used by these doctoral students were, on the whole, inadequate for the task of contributing to either the theoretical or the practical knowledge base in this field. This impression of weak knowledge accumulation was further reinforced by a citation analysis that found limited citations of the dissertations by other researchers in the field at large or by the dissertation authors themselves. These conclusions applied equally to EdD and PhD dissertations, regardless of the level of research university from which they were produced. Conclusions: The review adds empirical evidence of trends in research quality gathered over a 30-year period to the renewed debate over the purpose and direction of the doctoral dissertation in this professional field. Copyright © 2011 The University Council for Educational Administration.