TY - JOUR AU - Glewwe,Paul AU - Kremer,Michael AU - Moulin,Sylvie AU - Zitzewitz,Eric TI - Retrospective vs. Prospective Analyses of School Inputs: The Case of Flip Charts in Kenya JF - National Bureau of Economic Research Working Paper Series VL - No. 8018 PY - 2000 Y2 - November 2000 UR - http://www.nber.org/papers/w8018 L1 - http://www.nber.org/papers/w8018.pdf N1 - Author contact info: Paul W. Glewwe Dept of Applied Economics, U of MN 1994 Buford Ave. St. Paul MN 55108 E-Mail: pglewwe@umn.edu Michael Kremer Harvard University Department of Economics Littauer Center M20 Cambridge, MA 02138 Tel: 617/495-9145 Fax: 617/495-7730 E-Mail: mkremer@fas.harvard.edu Sylvie Moulin World Bank 1818 H Street, N.W. Washington, DC 20433 Eric Zitzewitz Department of Economics Dartmouth College 6106 Rockefeller Hall Hanover, NH 03755 Tel: 603/646-2891 Fax: 603/646-2122 E-Mail: eric.zitzewitz@dartmouth.edu AB - This paper compares retrospective and prospective analyses of the effect of flip charts on test scores in rural Kenyan schools. Retrospective estimates that focus on subjects for which flip charts are used suggest that flip charts raise test scores by up to 20 percent of a standard deviation. Controlling for other educational inputs does not reduce this estimate. In contrast, prospective estimators based on a study of 178 schools, half of which were randomly selected to receive charts, provide no evidence that flip charts increase test scores. One interpretation is that the retrospective results were subject to omitted variable bias despite the inclusion of control variables. If the direction of omitted variable bias were similar in other retrospective analyses of educational inputs in developing countries, the effects of inputs may be even more modest than retrospective studies suggest. Bias appears to be reduced by a differences-in-differences estimator that examines the impact of flip charts on the relative performance of students in flip chart and other subjects across schools with and without flip charts, but it is not clear that this approach is applicable more generally. ER -