Insee Analyses · September 2024 · n° 96

The effects of birth month on academic success at age 15: an international comparison

Not all children start school at the same age or with the same level of maturity. Since the entry date for first grade is the same for all children born in the same calendar year, a student born in January is almost a year older than a student born in December, which can be an advantage for learning.

According to the results of the PISA test analyzed in about fifteen countries, including France, the effects of age at school entry are lasting: on average, being one year younger at school entry lowers performance at age 15 by about 20 points in mathematics, science, and reading. In several countries, being younger at school entry also increases the risk of repeating a grade during their schooling and being exposed to bullying. The youngest students show weaker social and emotional skills and have less confidence in their abilities. For example, they are less likely to consider pursuing higher education.

However, the magnitude of these effects varies by country. Studies showed that certain school practices (such as longer school days, more crowded classes) might amplify the effects of age at school entry.