There is no robust empirical support for the effect of financial incentives on the decision to work in self-employment rather than as a wage earner. In the literature, this is seen as a puzzle. We offer a focus on the opportunity cost, i.e. the wages given up as an employee. Information on...

We extract estimation results on the Mincer earnings function from four earlier studies and add new results from a recent dataset. We analyse differences related to differences in earnings concepts, in sampling frame and differences among studies that cannot be explained. Jointly, the studies...