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Notre étude du concept de taux naturel de chômage a comme objectif une réflexion sur le concept et sa possible utilisation comme indicateur de politique économique. Après la réflexion faite sur le concept (I), nous présentons les principaux modèles théoriques qui déterminent le taux (II). Au-delà des problèmes soulevés par l’estimation économétrique, nous proposons, pour l’économie portugaise, une étude fondée sur des séries trimestrielles (III). Finalement nous concluons (IV). This paper presents some of the conclusions reached by us in the framework of a broader research on the Natural Rate of Unemployment (NRU). Our main aim is to ascertain the NRH properties as an economic indicator, placing special emphasis on the Portuguese economy. First we review the concept of NRU. Secondly we compare the two most important types of NRU models: the Phillips model, updated by Gordon’s “triangle” model (1997) and Layard, Nickell and Jackman’s model (1991) updated by Blanchard’s version (1999). The economic and social factors leading to the existence of a short or medium-run varying NRU (NAIRU) or to the non-existence of a long-run NRU (NAIRU) are emphasised. Thirdly, some of the major difficulties concerning the econometric analysis of the NRU are pointed out. Fourthly, with a non-linear version of Elmeskov method we obtain a very stable and predictable series of the NRU dependent on cyclical and trend output. The AIC criterion leads to a long memory model. A near-VECM model produces impulse responses that confirm our previous results of hysteresis in unemployment rate. Finally we conclude. |
