The Effect of Academic Redshirting on Math and Reading Achievement: An Analysis of Short-term and Long-term Impacts

Abstract

This paper investigates the effect of academic redshirting on test scores in math and reading. Academic redshirting is the practice of delaying formal schooling for an additional year before a student enters kindergarten. Using data from the Early Childhood Longitudinal Study—Kindergarten Class (ECLS-K), this analysis seeks to determine the causal impact of academic redshirting in the short-term and whether any gains persist over time. When investigating the effect of redshirting, three factors threaten the validity of estimates: selection based on observable variables, selection based on unobservable variables and the impact of age on achievement. In order to address these threats to validity, this paper implements three distinct methodologies: propensity score matching, regression discontinuity design and propensity score weighting. This paper offers a new and robust contribution to the redshirting literature because it utilizes a variety of methodological approaches and compares results across models. The results from all three approaches indicate that increased entrance age produces short-term positive effects on achievement. The positive effects of age, however, fade out and appear to reverse by eighth grade. Considering policy implications and unintended consequences, redshirting is not an effective policy intervention to increase student achievement.