Before revision:  The policy-relevant treatment effects may not be estimated at the regular parametric \sqrt{n and Vytlacil, 2010). In this light, we propose a regularized estimator. The regularization improves the convergence rate when the rate is slower than \sqrt{n .
After revision:  The policy-relevant treatment effects may not be estimated at the regular parametric \sqrt{n and Vytlacil, 2001, 2005, 2007), we apply the methods and theory of average derivative estimation to the framework of the policy-relevant treatment effects .