“…Indeed, individuals may reconsider their investment in education, fearing that the time and effort spent on obtaining a PhD is not sufficiently rewarded (Gaeta et al, 2022). This is a key issue as PhD holders are generally considered to play a strategic role in the expansion of the so-called 'knowledge economy' (Bansak et al, 2021;Ermini et al, 2017). Moreover, from a public finance perspective, the fact that many doctorate holders end up in jobs for which they are genuinely over-educated means that significant resources are wasted, especially as the cost of doctoral training is high and the share of public funding spent on doctorate holders is large (Caroleo and Pastore, 2018).…”