Late in 2007 New Visions for Public Schools, a New York City reform organization, received a grant from the C.S. Mott Foundation to organize select high schools and community partners into delivery systems that could improve student achievement. New Visions asked Policy Studies Associates, Inc. to provide research support for this effort in the form of a concise, field-tested conceptual framework for inter-organizational instructional collaboration. The resulting model is presented in Chapter 3 of this report. In developing the model, PSA researchers reviewed pertinent literature and conducted field work in four New York City high schools and in two Boston high schools. This report presents research results in three chapters. Chapter 1 introduces concepts and methods. Chapter 2 presents case studies of successful partnerships and summarizes practitioners' views about what does and does not work. Chapter 3 discusses study conclusions and implications. There are two appendixes; the first presents the literature in detail, and the second presents the methodological details of this investigation. (Contains 5 exhibits and 5 footnotes.) [This report was prepared for New Visions for Public Schools.]