“…Concerning the parameters in the PSTR framework, while individual xed eects are normally eliminated via withintransformation, the model is estimated by nonlinear least squares, because of the nonlinearity introduced by the transition function. A detailed and technical presentation of the PSTR can be found in Gonzalez et al (2017) and Teräsvirta (1994Teräsvirta ( , 1998 (for the time series case) and in Owusu et al (2023) with an application of PSTR to study a scal reaction function, where the regimes depend on public debt to GDP ratios.…”