The literature related to the development of education in the middle grades and to the features associated with the implementation of the middle school concept provides a theoretical grounding for the development and testing of an Innovation Configuration map for the middle school concept. The description provided of the historical development of middle-grades education presents the context for recent research studies and ongoing policy debate. In addition, features of the middle school concept as described within the literature are identified and an overview of salient research findings related to these features is given. A synthesis and critical review of previous research methodologies and findings reveal the need for further research. The purpose of the instrument development and testing process was to identify critical features of the middle school concept implemented in the context of standards and accountability. The instrument development and testing process investigated the nature of the implementation of middle school concept features, recognizing that actual practices in schools may vary somewhat without the schools losing their identity as middle level schools. The principle product of the process was the development of a diagnostic tool that may be used in future research to identify acceptable forms of implementation of the middle level philosophy of education. The instrument development and testing process employed research methodology based on the Concerns-Based Adoption Model (CBAM) of Hall and Hord (2006). Specifically, an Innovation Configuration map was developed identifying components of the middle level philosophy of education and describing variations in implementation of the components. / Ed. D.