期刊名称：Discussion Papers / University of Leicester, Department of Economics
出版年度：2014
出版社：Leicester
摘要：The method of instrumental variables (IV) and the generalized method of moments (GMM), and their applications to the estimation of errors-in-variables and simultaneous equations models in econometrics, require data on a sufficient number of instrumental variables that are both exogenous and relevant. We argue that, in general, such instruments (weak or strong) cannot exist.
