The Effect of Peer Socioeconomic Status on Student Achievement: A Meta-Analysis

Abstract

Previous studies on the effects on students’ test scores of their peers’ socioeconomic status (SES) have reported varying results. In order to understand why researchers have alternately found small effects, large effects, or no effects at all, a meta-regression analysis including an extensive database of 30 studies on the topic was conducted. Results show that the size of the compositional effect that researchers find is strongly related to how they measure SES and to their choice of model. Measuring SES dichotomously (e.g. free lunch eligibility) or including several average SES variables in one model leads to smaller effect estimates than using a thoroughly constructed composite that includes several of the dimensions of SES. Composition measured at cohort/school level is associated with smaller effects than composition measured at class level. Researchers estimating the compositional effect without controlling in their model for prior achievement or not taking into account the potential for omitted variables bias, risk overestimating the effect. On the other hand, including in a model a large set of covariates that are not well thought-over may lead to an underestimation of the compositional effect, since it artificially explains away the effect. Little evidence was found that effect sizes differ with sample characteristics such as test type (language vs. math) and country. Estimates for a hypothetical study, making a number of “ideal” choices, suggest that peer SES is an important determinant of academic achievement.

Keywords: meta-analysis, social class, academic achievement, compositional effect

JEL Classification: I2