The demand for certain types of health care services depends on decisions of both the individual and the health care provider. This paper studies the conditions under which it is possible to separately identify the parameters driving the two decision processes using only count data on the total...

This paper suggests a simple specification test to check the adequacy of the assumptions made about the distribution of individual effects in models where these unobservable random variables are integrated out by quadrature methods. Because the proposed test checks the specification of the...

Helpman, Melitz, and Rubinstein (2008)HMRpresent a rich theoretical model to study the determinants of bilateral trade flows across countries. The model is then empirically implemented through a two-stage estimation procedure. This note seeks to clarify some econometric aspects of the estimation...