Relative age and investment in human capital

This article provides evidence from four studies in Mexico on how the age of children relative to their school class—their “relative age”—produces an illusory gap in academic skills and affects the experiences of students, their choices, self-concept, and expectations. The first study shows that relative age confers an advantage in achievement tests at ages 12–15 that makes older students look academically better than their younger peers. The advantage would disappear if students were tested at the exact same age. The second study shows that, when 15-year-olds participate in a competitive merit-based mechanism to be allocated to public high schools, older students aim at and are more likely to be admitted to higher-quality schools. The third study shows that, during high school, age confers an advantage in GPA that decreases but does not disappear as students reach age 18. Lastly, the fourth study shows that, at age 18, relatively older students score higher in achievement tests and character skills scales, and they have better labor market expectations and more ambitious educational aspirations—a novel result. To the world and themselves, relatively older students appear worthy of greater human capital investment. Some implications of these results are discussed.