Before revision:  Stute, 1984), and is under mild conditions consistent and asymptotically normal with a rate of convergence that is the same regardless of the degree to which selection depends on unobservables in the outcome equation . The first-order behaviour of the new estimator, unlike those of other proposals in the literature, does not depend on explicit assumptions regarding the relative tail behaviours of the determinants of selection . Simulation evidence and an empirical example are included.
After revision:  Stute, 1984), and is under mild conditions consistent and asymptotically normal with a rate of convergence that is the same regardless of the degree to which selection depends on unobservables in the outcome equation . Simulation evidence and an empirical example are included.