A teoria económica explica que quando a economia cresce abaixo do seu potencial, o excesso de capacidade pressiona os preços e gera episódios de desinflação – uma situação em que a taxa de inflação vai progressivamente diminuindo. Em Why don’t we have deflation, Paul Krugman tenta explicar por que é que esta relação entre actividade económica e preços parece perder validade quando a inflação se aproxima do zero. Tem tudo a ver com rigidez nominal.
One immediate thing to look at was to see whether what was happening to inflation in the United States was consistent with historical experience of deep slumps that we know involved the economy operating well below capacity for an extended period. And it turned out that the Japanese deflation (which has never been very fast in any case) is pretty much unique. The IMF looked at Protracted Large Output Gaps — PLOGs — and found that in general inflation gets squeezed toward, but not below, zero.
And our own history actually points in the same direction: the 1930s were marked by sharp deflation in the early years, but considerable inflation as the economy partially recovered, even though unemployment remained very high.
So inflation seems “sticky”. But why? One immediate thought was that we might be looking at the effects of downward nominal wage rigidity: employers are very reluctant to engage in actual wage cuts. Way back in 1996 Akerlof, Dickens and Perry suggested that this would make inflation stubborn at low rates, breaking the usual link between high unemployment and disinflation.
Still, how can you tell if sticky inflation reflects sticky wages, as opposed to being the result of an economy that really doesn’t have very much slack? The answer is that sticky wages should leave a “signature” in the wage data: a large number of workers whose wages neither rise nor fall, and a rising number of such workers as the economy slumps. Sure enough, researchers at the San Franciso Fed found exactly that.