The returns to entrepreneurship are monetary and non-monetary. We offer new evidence on these returns using a large sample of male twins. Our within-twin analysis suggests that OLS estimates are downwards, and panel data estimates upwards biased. The within-twin estimates imply that...

Shared-frailty survival models specify that systematic unobserved determinants of duration outcomes are identical within groups of individuals. We consider random-effects likelihood-based statistical inference if the duration data are subject to left-truncation. Such inference with...