Responsible researcher: Bruno Benevit.
Original title: The Effect of Age at School Entry on Educational Attainment: An Application of Instrumental Variables with Moments from Two Samples.
Authors: Joshua D. Angrist and Alan B. Krueger.
Location of Intervention: United States.
Sample Size: 112,000 children.
Sector: Education Economics.
Variable of Main Interest: Education.
Type of Intervention: Age at school entry.
Methodology: IV
Summary
Education plays a fundamental role in several social determinants of people throughout their lives. Given its importance, the age at entry into the education system may be a relevant factor in explaining the level of education achieved in an individual's adult life. Mandatory school attendance policies can affect this determinant. In this sense, this study considered data from the 1960 and 1980 United States Census to analyze how the country's mandatory school attendance law impacted the schooling of affected cohorts. Using instrumental variable models formulated by the authors, the results suggest that mandatory attendance laws induce approximately 10% of students to remain in school.
Formal education is fundamental not only for individuals, but for society as a whole. Given its importance, school entry age is a significant factor that can influence students' educational performance, having long-term repercussions for them. Therefore, compulsory school attendance policies have great potential to influence this behavior.
In the context of the United States, the authors of this study presented a model that assumes that children enter school in the fall of the year they turn six and are required by law to remain in school until they turn sixteen (ANGRIST; KRUEGER, 1992). . In this situation, a child's date of birth can directly affect the amount of time they will spend in school before reaching the minimum age to drop out of school. Students born at the beginning of the year, who turn sixteen earlier, tend to spend less time in school compared to those born at the end of the year, resulting in different levels of education achieved. This phenomenon creates a natural experiment that allowed researchers to investigate how school entry age impacts individuals' educational trajectories.
Studies have shown that many students drop out of school as soon as they reach the minimum legal age, suggesting that compulsory school attendance laws play a key role in keeping these students in school longer.
According to Angrist and Krueger (1991), data from the 1960, 1970 and 1980 censuses revealed that school dropout rates increase significantly around the sixteenth birthday in states where this is the minimum age allowed to leave school. In contrast, states with stricter requirements, which extend the minimum age to seventeen or eighteen, have lower dropout rates. This evidence indicates that school entry age and compulsory attendance policies are interconnected, influencing not only when students begin their studies, but also how long they remain in school, thus affecting their overall educational levels and future potential.
To estimate the relationship between school entry age and education obtained, data from two United States censuses were used. The sample containing school entry age was drawn from the 1960 Census, while the sample containing years of education was drawn from the 1980 Census. Both data sets were restricted to males born between 1946 and 1952. Focused on in the cohort of men born between 1946 and 1952, as they were in elementary school during the 1960 Census.
To determine school entry age, entry age patterns in two groups of states with different cutoff dates for first grade admission were compared. States that admitted children who turned 6 by September 30 or October 1 were compared with states that allowed children who turned 6 by December 31 or January 1. These variations helped analyze the influence of state laws on school entry age.
The youngest child in the 1960 sample was 7 years old, above the legal minimum age to attend school in most states. The first grade entry age was calculated based on the student's age and grade level, assuming that no child was held back or advanced after entering school. The approach used takes into account age, measured in quarters on Census Day (April 1, 1960), and the grade in which the student was enrolled. Years of schooling completed were obtained from the 1980 Census, although this census reports only years completed, not quarters of schooling.
The study used the instrumental variables (IV) method to estimate the relationship between school entry age and years of schooling completed. The sample considered included men born between 1946 and 1952, with the age at entry into first grade estimated based on information from the 1960 Census and the years of schooling obtained from the 1980 Census. Thus, this method was based on the assumption that children were not retained or advanced in grade after entering school, allowing the entry age to be calculated based on the age and grade reported in the census.
The use of instrumental variables, in this case, allows us to estimate the relationship between the age at school entry and the years of schooling completed, controlling possible correlations between the age at entry and other unobserved factors that may influence educational results. This approach offers a robust way to investigate the impact of school entry age, even in the absence of perfect data on the exact school entry age.
To validate these estimates, entry age patterns in states with different cutoff dates for first grade admission were compared. States with cutoff dates in the third quarter were compared to states with cutoff dates in the fourth quarter, analyzing how these cutoff policies affect children's entry ages. Comparing entry age patterns between these two groups of states provides an additional check on the accuracy of heterogeneously entered age estimates, allowing for the estimation of effects associated with different entry ages.
The results of the study on school entry age indicated the existence of a negative relationship between school entry age and years of schooling completed. Specifically, the estimates revealed that, in general, children who enter school at an older age tend to complete fewer years of education. Analyzes were performed using different specifications of cohort trends in education, and most specifications resulted in significant coefficients, reinforcing this relationship.
The analysis also showed that this relationship remains robust even when controlling for different model variations and adjustments for cohort trends. Furthermore, the estimates obtained remained significant when considering interactions between year and quarter of birth with place of birth, and model fit tests suggest that the assumption of seasonality at birth as a valid instrument for school entry age is plausible. . These results support the model proposed by the authors that relates the school entry age to the years of education completed, suggesting that minimum school entry age policies can have significant impacts on the educational trajectory of students.
In this article, the authors investigated the impact of school entry age on years of schooling completed. The results presented indicated that individuals who enter school at older ages tend to achieve a lower level of education. This effect persists even after controlling for cohort trends and other demographic variables. Additionally, the authors found evidence that approximately 10% of men born between 1946 and 1952 were impacted by compulsory education laws, remaining in school for an additional period as a result of these public policies.
The evidence presented in this article helps to understand the factors that influence educational performance, providing support for public policy makers. The authors highlight that, given the impact of school entry age, reviewing minimum age policies for entry can optimize educational results. Furthermore, adapting these policies can help implement measures that better align educational requirements with child development, contributing to the overall improvement of the educational system.
References
ANGRIST, JD; KRUEGER, AB Does Compulsory School Attendance Affect Schooling and Earnings? The Quarterly Journal of Economics , vol. 106, no. 4, p. 979–1014, 1991.
ANGRIST, JD; KRUEGER, AB The Effect of Age at School Entry on Educational Attainment: An Application of Instrumental Variables with Moments from Two Samples. Journal of the American Statistical Association , vol. 87, no. 418, p. 328–336, jun. 1992.
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