We propose a new generalization of the concept of cointegration that allows for the possibility that a set of variables are involved in an unknown nonlinear relationship. Although these variables may be unit-root non-stationary, there exists a nonlinear combination of them that takes account of...

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...

Misspecifications of econometric models can lead to biased coefficients and error terms, which in turn can lead to incorrect inference and incorrect models. There are specific techniques such as instrumental variables which attempt to deal with some individual forms of model misspecification....