This paper uses the logistic smooth transition GARCH model to study the time-varying volatility of the USS?P 500 index. In the LSTGARCH specification, the parameters are function of some information variables that help capturing the conditional return volatility. Tests of standard GARCH models...

We use the control function approach to identify the average treatment effect and the effect of treatment on the treated in models with a continuous endogenous regressor whose impact is heterogeneous. We assume a stochastic polynomial restriction on the form of the heterogeneity but, unlike...