Beyond maturity: How school-entry rules reshape the life course

The age at which children start school is often treated as a routine administrative detail. Yet a growing body of economic research shows that school-entry rules can have lasting consequences throughout life. Two recent IZA Discussion Papers examine this question from different angles, revealing a fascinating scientific dialogue.

The first paper synthesizes decades of global research, demonstrating that school-entry effects reflect how children are positioned within national education systems rather than simple classroom maturity. The second paper serves as the ultimate test case for this theory. Focusing on Germany, it delivers a major surprise: even in a rigid academic environment, a later school start alters women's lifetime earnings—not by changing their school track, but by shifting the timing of when they start a family.

Together, these studies highlight that the effects of school starting age extend well beyond the classroom, shaping educational trajectories, labor market outcomes, and family formation through a complex interaction of individual development and institutional rules.

Understanding the economics of school starting age

In The Economics of Age at School Entry: Insights from Evidence and Methods (IZA DP No. 18373), authors Mariagrazia Cavallo, Elizabeth Dhuey, Luca Fumarco, Levi Halewyck and Simon ter Meulen review and analyze the global economic literature on school-entry age.

Because school systems use fixed cutoff dates, children born just before and just after the cutoff can differ in age by almost a year when they begin school. A large body of research shows that this age difference can influence many outcomes later in life, including education, labor-market performance, health, social relationships, crime, and family formation. However, findings across studies often vary widely, making interpretation difficult.

Rather than focusing on individual estimates, the authors organize the evidence using a unifying framework that views the school-entry age through four closely related dimensions: a child's actual age when starting school, their relative age compared to classmates, the specific age when outcomes are measured, and the total time they have spent in school by that point. Crucially, the authors note that these different facets are tightly intertwined in practice, making it incredibly difficult for standard research designs to isolate any single empirical mechanism. Instead, most studies capture a bundled mix of age-related and institutional factors simultaneously.

A central lesson from this global review is that age-at-school-entry effects reflect how individuals are positioned within educational and institutional systems over time, rather than simple maturity advantages. For instance, younger entrants face a higher risk of misdiagnosed ADHD due to relative maturity comparisons within the classroom, while older entrants often encounter age-based dropout rules that can prematurely shorten their educational trajectories. This perspective explains why findings differ across countries and has important implications for how education systems are designed.

The German case: Effects on the gender pay gap

Germany is a particularly interesting case because students were sorted early into different secondary school tracks, making the timing of school entry potentially more important than in less rigid systems. In School Starting Age and the Gender Pay Gap over the Life Cycle (IZA DP No. 18503), however, Kamila Cygan-Rehm and Matthias Westphal reveal that starting school later has little overall effect on men’s lifetime earnings.

Men who begin school later initially earn less, largely because they enter the labor market later and accumulate less early work experience, but over time this disadvantage mostly disappears. By the prime working years, the earnings gap is no longer statistically meaningful. In other words, a later school start mainly shifts the timing of earnings rather than changing total career success.

For women, however, the story looks different. Women who start school later enjoy higher earnings during much of their working lives, especially in early and mid-career. These gains are large enough to offset the initial delay in labor market entry, resulting in a moderate compression of the gender pay gap over the life course.

A simple explanation would be that women benefit more because they gain more education from starting later, but the study does not support that view. Men and women show broadly similar effects on educational attainment; later school entry slightly increases years of schooling and the likelihood of completing more academic tracks, but these educational gains do not explain the gender difference in earnings. Nor do the results point to major gender differences in the kinds of jobs or firms people end up in.

Instead, the evidence points to family formation and labor market attachment around motherhood. The researchers find that women who start school later also tend to have their first child later. This delay is modest in size, but it occurs at a crucial point in the career, when wages typically grow quickly and work experience has especially high returns. A later first birth appears to help women stay attached to the labor market during this important period, which in turn seems to produce lasting earnings benefits.

This mechanism matters because motherhood remains one of the main drivers of long-run gender inequality in labor markets. In West Germany, the cohorts studied (born between 1945 and 1965) grew up in a context of conservative gender norms, limited childcare provision, and substantial career penalties for mothers. In such an environment, even a small shift in the timing of childbirth can make a meaningful difference to women’s career trajectories, suggesting that later school entry may have given some women a better foothold in the labor market before family responsibilities interrupted their careers.

Designing smarter institutional frameworks

Ultimately, both research teams emphasize that there is no single "optimal" school starting age. The estimated impacts of school entry are rarely clean maturity advantages; instead, they reflect a complex bundle of age-related dynamics and institutional mechanisms that shape how individuals are positioned within educational and socioeconomic systems over time.

Rather than calling for blanket policy shifts or simple deferrals, these findings highlight how administrative rules interact with specific institutional environments—particularly those governing education, work, and family life. In rigid contexts, seemingly minor differences at the very start of life can accumulate over decades, shifting the timing of key biographical milestones and ultimately influencing who stays in work, who earns more, and how inequalities evolve across the life cycle.