Schools frequently increase instructional time to improve students' numeric and reading performance, but there is little evidence on the eectiveness of such an increase. This study evaluates 'Playing for Success', an extended day program for underachieving pupils that uses the football environment as a motivating force. Primary school pupils with low motivation and self-esteem are oered practical and sports related teaching content for 30 additional hours. The program is evaluated using a randomized controlled eld experiment. The results indicate that Playing for Success does not signicantly improve math and reading performance of primary school students. ueywordsX e™hievementY ghild hevelopmentY iv—lu—tionY wotiv—tionY ixtended ƒ™hool h—yF