The effect of school entrance age on educational outcomes: Evidence using multiple cutoff dates and exact date of birth

Using Israeli data, we estimate the effect of school entrance age (SEA) on student outcomes. Unlike much of the recent literature, our unique identification strategy separates the SEA effect from date of birth effects. We find that delaying school entry by one year increases fifth grade test scores in Hebrew by 0.29 standard deviations and in math by 0.16. Interestingly, while the advantage in Hebrew decreases in eighth grade, in math it almost doubles. We show that although the bias induced by failing to control for date of birth effects is generally rather small, in some cases it is quite notable. This bias could have mistakenly led us to conclude that the SEA effect on math test scores slightly decreases from fifth to eighth grade while it actually substantially increases.