Citation: Program Development and Evaluation, Analysis of Retrospective Post-then-Pre Data, Quick Tips #30, University of Wisconsin-Extension, Madison, WI. This document is part of a series of Tip Sheets developed by the Program Development & Evaluation Unit of University of Wisconsin Cooperative Extension. It contains an analysis of a retrospective post-then-pre data. Copyright (or ©) 2005 Board of Regents of the University of Wisconsin System, d/b/a Division of Cooperative Extension of the University of Wisconsin-Extension #HowTo #ExtensionEducationEvaluation