In a recent study, Mariassunta Giannetti and Andrei Simonov of the Stockholm School of Economics show the magnitude of differences in levels of entrepreneurship across Swedish municipalities. They define entrepreneurs as people who report income from a company that they control and work in at least part-time, and find that the proportion of entrepreneurs in the population differs substantially across the 289 municipalities that they studied, ranging from 1.5% to 18.5%.