In his text published in Edukacja, 141(2), 2017 („Education reform and inequality: fifteen years of new lower secondary schools in Poland”), Zbigniew Sawiński analyses data from the 2000 to 2012 editions of the OECD PISA study and argues that lower secondary school reform has not reduced educational inequalities in Poland. The importance of students’ social origin remained at the same level as before the reform, the impact of social origin on the choice of type of secondary school remained the same, and an increasing differentiation of lower secondary schools did not lead to an increase in educational inequalities. I present methodological arguments and the results of a re-analysis of PISA data, indicating changes in wider educational inequalities. Between 2000 and 2012: (a) the strength of association in the performance of 15-year-olds with the socio-economic status of students’ families did not change, but (b) the variation of results decreased, which was mainly due to the improved performance of the lowest performing students, (c) the differences between students of high and low socio-economic status decreased, (d) the influence of social origin on the choice of the type of upper secondary school decreased. The effects of socio-economic status on upper secondary school choice is largely direct: it is not mediated by the educational achievements of students. The commentary also highlights the complexity of lower secondary school reform, which was not limited to the introduction of such schools. I indicate the role of factors that make it difficult to interpret the results of the reform in causal terms – particularly the role of unobserved variables related to the changes in the learning environments of subsequent cohorts of students.