Quasi-Experimental Evaluation Without Regression AnalysisRohrer, James E. PhDJournal of Public Health Management and Practice: March-April 2009 - Volume 15 - Issue 2 - p 109–111 doi: 10.1097/01.PHH.0000346006.59275.1e Commentary Buy SDC Abstract In Brief Author InformationAuthors Article MetricsMetrics Evaluators of public health programs in field settings cannot always randomize subjects into experimental or control groups. By default, they may choose to employ the weakest study design available: the pretest, posttest approach without a comparison group. This essay argues that natural experiments involving comparison groups are within reach of public health program managers. Methods for analyzing natural experiments are discussed. The purpose of this commentary is to argue that natural experiments abound, that they offer better validity than simple pre-post designs, that their use should be taught in public health graduate programs, and that they should be employed more frequently in public health practice. James E. Rohrer, PhD, is Professor of Family Medicine. He has served on the faculty of four universities, teaching courses in health administration and program evaluation. He has worked with health departments in Iowa and Texas and is also the author of more than 150 publications, including a book (Planning for Community-Oriented Health Systems [American Public Health Association, 2000]). Most of his research has addressed community health needs or program evaluations. Corresponding Author: James E. Rohrer, PhD, Employee and Community Health, Mayo Clinic – Rochester, 200 First St SW, Rochester, MN 55905 (email@example.com). Disclaimer: No human subjects data were analyzed for this study. © 2009 Lippincott Williams & Wilkins, Inc.