The article analyses the (third) Coleman Report on private and public schools. The report scrutinises the relationship between private and public schools and shows that private school students show better academic achievement. Coleman concluded that these findings provided a strong argument in favour of public financial support for private schools. However,he identified a number of school characteristics that he believed to be related to student achievement. According to his analysis, these characteristics were not limited to privateschools; public schools exhibiting the same characteristics also had good results. Coleman interpreted the available data in favour of financial aid to private schools, although this was not the only possible interpretation. An alternative conclusion would have been to encourage these characteristics in public schools. Why did Coleman disregard this possibility? Why did he deviate from his usual scientific rigour? The present article suggests that there appear to be two reasons for the narrow interpretation of the relationship between public and private schools in Coleman’s third report. The first lies in Coleman’s notion of contemporary society as a constructed system in which every individual actor holds a place in the structure and requires incentives in order to act to the benefit of society. In the case of education, the goal of the institution is to ensure the high cognitive achievement of students, and the incentive is related to choice and competition. The second reason is related to Coleman’s vision of sociology as a discipline aiding the construction of an effective society.