Early effects of an early start: Evidence from lowering the school starting age in Poland

This paper investigates some early outcomes of the reform to lower the school starting age in Poland. It explores data on the school performance of 6- and 7-year-old pupils, collected in the transitory period of the reform, when parents were welcomed to enroll their 6-year-old children in the first grade on a voluntary basis. It was found that the parental decision is largely based on a rational assessment of the child’s readiness for school. There is strong evidence of positive selection for early enrollment in the 1st grade.

At the beginning of the school year early entrants perform worse than 7-year-old children, but after one year the gap between the two age cohorts becomes substantially reduced in all subjects tested. Older students do perform better, but the separately measured effect of an early school start also seems to be beneficial. We point out a selection of unobservables as a possible explanation of the results obtained.