This paper considers the use of instrumental variables to identify a correlated random coefficients model in which coefficients are correlated with (or stochastically dependent on) the regressors. A correlated random coefficients model is central to the human capital earnings model. Conditions...

This paper considers the use of instrumental variables to estimate the mean effect of treatment on the treated, the mean effect of treatment on randomly selected persons and the local average treatment effect. It examines what economic questions these parameters address. When responses to...