¿Porque Entran en Crisis los Modelos de Equilibrio General DSGE? Un Post de VOXEUX.ORG

Un artículo interesante que salió en Junio del 2014, en la web del conocido Voxeau.org, con el título siguiente:

 " Why DSGEs crash during crises"

Analiza efectivamente cuales son los problemas de estos viejos modelos que pretendian ser el "modelo del todo" en la ciencia económica, sin embargo muchos de ellos, seguidos por los Bancos Centrales, en países con graves crisis económicas, no han podido responder  a estas, no han podido predecir ni acercarse a las fluctuaciones de los mercados financieros, como tampoco en lo relevante a las políticas fiscales.

Los profesores de la Universidad de Oxford (Reino Unido) muestran el porque fallan estos modelos, he aquí un pequeño extracto:

"Many of the theoretical equations in DSGE models take a form in which a variable today, say incomes (denoted as y_t), depends inter alia on its ‘expected future value’. (In formal terms, this is written as E_ty_t+1], where the ‘t’ after the ‘E’ indicates the date at which the expectation is formed, and the ‘t+1’ after the ‘y’ indicates the date of the variable). For example, y_t may be the log-difference between a de-trended level and its steady-state value. Implicitly, such a formulation assumes some form of stationarity is achieved by de-trending.¹

Unfortunately, in most economies, the underlying distributions can shift unexpectedly. This vitiates any assumption of stationarity. The consequences for DSGEs are profound. As we explain below, the mathematical basis of a DSGE model fails when distributions shift (Hendry and Mizon 2014). This would be like a fire station automatically burning down at every outbreak of a fire. Economic agents are affected by, and notice such shifts. They consequently change their plans, and perhaps the way they form their expectations. When they do so, they violate the key assumptions on which DSGEs are built."

Para mayor evaluación sobre este importante tema, aquí la dirección de Voxeaux.Org.

http://www.voxeu.org/article/why-standard-macro-models-fail-crises