In this work, we examine the effect of the age at which children begin school on the later scholastic success. Two different records are base of the empirical analyses for Germany, that contain Individualdaten of students at the end of the elementary school and in the continuing school. The methodical action relies on Instrumentalvariablenschätzungen, that use the exogenous variation of the birth month. This extension uses the connection between birth month and age at which children begin school that exists on the basis of legal target date regulations. It appears that a higher age at which children begin school affects significantly positively the later scholastic success: So lie climbs for student, who are schooled with seven, instead of at six years of age, that to visit test results in the standardized Grundschul- harvest investigation IGLOO by approximately 0.4 standard deviations more highly than at the relatively younger students and the probability, a secondary school, for the more old schooled children by approximately 12 points. (Patrick A.Puhani/Andrea M.Weber in Economics Working Papers at FB WiWi, Uni Hannover