A data point below (above) the 45 degree line indicates that the change in the educational composition of the workforce is associated with a fall (rise) in earnings inequality. The Drivers of Labour Earnings Inequality - An Analysis Based on Conditional and Unconditional Quantile Regressions", OECD Economics Department Working Papers, No. An upper-secondary degree is today typically considered the minimum needed to find a decent job (OECD, 2010a).17 Moreover, while the returns to lower-secondary education have declined over time, those to post-secondary education have surged (e.g. Lemieux, 2006/?, A simple panel regression analysis that regresses the average rate of return to a tertiary degree on the share of employed and unemployed individuals holding such a degree and country-fixed effects lends support to this negative relationship.