A few definitions have been suggested for the transition function in the literature. We start by considering G( ,c,st ) as a logisticfunction of order one: G( , c, st ) = [1 + exp{− (st − c)}]−1 , > 0. (13) This kind of STR model is called a logistic STR model or an LSTR1model. This transition function is an increasing function of st , wherethe slope parameter indicates the smoothness of the transitionfrom one regime to another, i.e. how rapid the transition from zeroto unity is, as a function of st . Finally, the location parameter cdetermines where the transition occurs. Considering this framework, the LSTR1 model can describerelationships that change according to the level of the thresh old variable. Assuming that the transition variable is the level ofinflation (st = t ), then the LSTR1 model is able to describe an asym metric reaction of the central bank to a high and to a low inflationregime. Given the important weight that the central banks analysedin this study put on inflation, we expect to find significant differ-ences in the behaviour of these banks when (expected) inflation isdeviating considerably from a certain threshold.
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