the relationship between the entrepreneurship rate and educational attainment is U-shaped. This holds across data sources, time periods, and (some) countries, giving the regularity some support. Using recent data from the new Panel Study of Entrepreneurial Dynamics (PSED), Campbell and De Nardi (2009) also find a U-shape of the probability of being in the process of starting a business with respect to schooling (see their Fig. 2).