I metodi di stima del PIL potenziale tra fondamenti di Teoria economica e Contenuto empirico

The paper explores into the empirical estimates of potential output currently produced by international economic institutions. As for the theoretical foundations of the notion, the paper endeavours to show how the shift from the Keynesian notion of potential output as a ceiling on actual production to the idea (to be found in NAIRU models) of a permanent tendency of actual production to gravitate towards potential production has affected the very way in which estimates are currently built. As for the empirical content of the estimates, the survey of the main methods through which potential output is currently estimated aims at showing that the difficulties connected with the attempt to identify empirically the “long-period supply factors” that according to theory should determine the trend, imply that current estimates of potential output often amount to nothing more than elaborate techniques of extraction of a statistical trend from the data on actual output, thus in effect offering an ex-post synthesis of what happened, rather than the ideal benchmark with which to compare actual realizations. This sort of estimates are likely to provide a poor guide to the action of policy-makers.