As a research and technical assistance organization, CNA Education would be the last to deny the importance of good data and the first to applaud efforts to improve the quality and scope of the data available. Solid data are critical to CNA's mission to further general understanding of the efficacy of specific education reform initiatives and to address the needs of their district-level and state-level customers and constituents for a clearer assessment of their own specific efforts and of the available options for improving their education outcomes. The three papers in this collection ("The State Data Analysis Gap: A Threat to Education Reform" by Arthur Sheekey and Michael Allen; "Getting State Education Data Right: What We Can Learn from Tennessee" by Kyle Southern and Joe Jones; and "The Equitable Distribution of Effective Teachers: Can States Meet the Research Challenges Required for Success?" by Michael Allen) make the strong case, however, that the availability of good data is not all that policymakers and educators need for their decisions. In addition, they need to understand the limitations of their data and how to use and interpret them appropriately. And they must ask--and answer to their satisfaction--a number of conceptual and technical questions that have implications for the validity, interpretation, and very meaning of the data they seek to use.