Twins-based estimates of the return to schooling feature prominently in the labor economics literature. The validity of such estimates hinges critically on the assumption that within-pair variation in schooling is explained by factors which are unrelated to wage earning ability. This paper...

Casual observation suggests that people are more generous with their time than with their money. In this paper we present experimental evidence supporting the hypothesis. A third of our subjects demand no compensation for non-monetary investments, whereas almost all subjects demand compensation...