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...

Time-varying coefficient (TVC) estimation is a technique that has been developed to produce consistent estimates of parameters in the simultaneous face of measurement errors, unknown functional form and omitted variables. Previous work on the technique has not paid explicit attention to the...