The OECD carried out an analysis of reading test results taken by children in developed countries, which showed that 15-year-olds who had attended pre-primary education were on average a year ahead at school in reading.
This was the case even after children's social and economic backgrounds were taken into account.
The report said, 'The difference between students who had attended for more than one year and those who had not attended at all averaged 54 score points in the PISA reading assessment - or more than one year in formal schooling (39 score points).
'While most students who had attended pre-primary education had come from advantaged backgrounds, the performance gap remains even when comparing students from similar backgrounds.
'After accounting for socio-economic background, students who had attended pre-primary school scored an average of 33 points higher than those who had not.'
The research also found that disadvantaged children have less access to pre-primary education than advantaged ones in almost every country.
The study found the relationship between attending pre-primary education and better student performance at age 15 is strongest in countries that offer early years education to a large proportion of children, over a longer period of time, that have smaller pupil:teacher ratios in pre-primary school and that invest more per child in pre-primary education.
'School systems that have a ten percentage-point advantage in the proportion of students who had attended pre-primary school score an average of 12 points higher in the PISA reading assessment,' the report said.