Popular wisdom holds that publishers revise college textbooks mainly to kill off the secondary market for used books. While this behavior might be profitable if consumers are myopic, uninformed or have high short-run discount rates (that exceed the publishers'), neoclassical authors have noted...

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....