In Spring 2010, the Delaware Education Research and Development Center conducted an evaluation of Delaware's PBS project, an initiative focused on developing a school-wide system of strategies to reduce behavior problems and foster a positive school climate. The study focused on facilitators and barriers to PBS implementation, and also included analyses to examine the relationship between PBS and school suspensions. This report first provides background on the principles of the original Positive Behavior Support program and the history of its implementation in Delaware, and then presents the evaluation questions, briefly outlines the methods used, and describes the results. The report closes with a postscript reflection on the findings from a PBS expert and member of the DE-PBS leadership team. Appended are: (1) Detailed Description of Methods for Question 1--Contributors and Barriers; (2) Questions Used in Administrator, Coach, PBS Team, Teacher, and Student Interviews; (3) Delaware Assessment of Strengths and Needs for Positive Behavior Supports; (4) PBS Technical Assistance Survey; (5) Illustrative Quotes for Contributors and Barriers Theme and Sub-Themes; and (6) Details of Analyses for Question 2--Disciplinary Infractions. (Contains 7 figures, 15 tables, and 4 footnotes.) [For "Positive Behavior Support in Delaware Schools: Developing Perspectives on Implementation and Outcomes. Executive Summary", see ED535260. This study was funded by Delaware State Legislature.]