This paper employs conditional second moments to identify the impact of education in wage regressions where education is treated as endogenous. This approach avoids the use of instrumental variables in a setting where instruments are frequently not available. We employ this methodology to...

The question of whether two drugs namely alcohol and tobacco are used as complements or substitutes is of crucial interest if side-effects of anti-drug policies are considered. Numerous papers have empirically addressed this issue by estimating demand systems for alcohol and tobacco and...

This paper examines rates of return to schooling in Kazakhstan using OLS and instrumental variable (IV) methodologies. We use spouse's education and smoking as instruments. We find that spouse's education is a valid instrument and that conventional OLS estimates that assume the exogenous nature...

The question of whether two drugs namely alcohol and tobacco are used as complements or substitutes is of crucial interest if side-effects of anti-drug policies are considered. Numerous papers have empirically addressed this issue by estimating demand systems for alcohol and tobacco and...

Empirical work on the wage impact of training has noted that unobserved heterogeneity of training participants should play a role. The expected return to training, which partly depends on unobservable characteristics, is likely to be a crucial criterion in the decision to take part in training...

In practice structural equations are often estimated by least-squares, thus neglecting any simultaneity. This paper reveals why this may often be justifiable and when. Assuming data stationarity and existence of the first four moments of the disturbances we find the limiting distribution of the...

This paper examines the properties of instrumental variables (IV) applied to models with essential heterogeneity, that is, models where responses to interventions are heterogeneous and agents adopt treatments (participate in programs) with at least partial knowledge of their idiosyncratic...