“…In the pure time series applications in which researchers have examined asset price movements, interest rate changes and monetary policy, the focus is on inertia, and takes the form of an autoregressive model in the latent variable regression. The Czado, Heyn and Müller (2005) and Müller and Czado (2005) study of migraine headache severity is also presented in this framework, though their study can be usefully viewed as falling somewhere between the time series analysis of, e.g., Eichengreen et al's (1985) study of bank rate policy and the recent panel data studies, e.g., of health satisfaction. In panel data settings, such as Contoyannis, Jones and Rice (2004), the model is directed at state dependence, and, instead, takes the form of lagged effects in the observed variables.…”