Importantly, the results are robust to accounting for the country's level of development as a potential confounding factor (this is obtained in column 3, augmenting the specification by the interaction between PEB and the log of GDP in the country), and to accounting for possible underlying country-specific trends in inequality and educational achievements (col. Marginal effects obtained using estimates in col.1 of Table 3. Low PEB: neither parent has attained upper secondary education, Medium PEB: at least one parent has attained secondary and post-secondary, non-tertiary education, High PEB: at least one parent has attained tertiary education. The bars indicate 95% confidence intervals.