Já tinha ouvido falar que, apesar do grande consenso em torno da necessidade de controle da inflação, a evidência empírica parece descartar efeitos nocivos desta sobre crescimento até níveis moderados de aumento dos preços. Resolvi hoje ir atrás das evidências.
Nesse momento em que inflação não é preocupação primária, esse post pode parecer meio fora de lugar. Mas acho que pode permitir uma discussão interessante sobre credibilidade do BC, bem como sobre nível de gasto compatível com uma taxa de inflação tolerada mais elevada.
Evidência 1: Nonlinear Effects of Inflation on Economic Growth, by Michael Sarel © 1996 International Monetary Fund.
This paper examines the possibility of nonlinear effects of inflation on economic growth. It finds evidence of a significant structural break in the function that relates economic growth to inflation. The break is estimated to occur when the inflation rate is 8 percent. Below that rate, inflation does not have any effect on growth, or it may even have a slightly positive effect. When the inflation rate is above 8 percent, however, the estimated effect of inflation on growth rates is significant, robust, and extremely powerful. The paper also demonstrates that when the existence of the structural break is ignored, the estimated effect of inflation on growth is biased by a factor of three.
Contra-Evidência 1: Warning: Inflation May Be Harmful to Your Growth, by Atish Ghosh and Steven Phillips © 1998 International Monetary Fund.
While few doubt that very high inflation is bad for growth, there is less agreement about the effects of moderate inflation. Using panel regressions and allowing for a nonlinear specification, this paper finds a statistically and economically significant negative relationship between inflation and growth, which holds robustly at all but the lowest inflation rates. A "decision-tree" technique identifies inflation as one of the most important determinants of growth. Finally, short-run growth costs of disinflation are only relevant for the most severe disinflations, or when the initial inflation rate is well within the single-digit range.
Evidência 2: Threshold Effects in the Relationship Between Inflation and Growth, by Mohsin S. Khan and Abdelhak Senhadji 2000 © International Monetary Fund (IMF)
This paper reexamines the issue of the existence of threshold effects in the relationship between inflation and growth, using new econometric techniques that provide appropriate procedures for estimation and inference. The threshold level of inflation above which inflation significantly slows growth is estimated at 1-3 percent for industrial countries and 7-11 percent for developing countries. The negative and significant relationship between inflation and growth, for inflation rates above the threshold level, is quite robust with respect to the estimation method, perturbations in the location of the threshold level, the exclusion of high-inflation observations, data frequency, and alternative specifications.
Evidência 3, mais atual: Barro (2001) "Handbook of monetary and fiscal policy"
Utiliza variáveis instrumentais para dar conta da endogeneidade da inflação, encontrando efeito significativo e negativo sobre crescimento, mas de magnitude bastante reduzida: um aumento de 10 pontos percentuais da inflação reduziriam o PIB em 0.2% ao ano, em média.
Resumo da ópera: A despeito da contra-evidência 1, parece haver emergido relativo consenso de que, excetuando-se episódios de inflação realmente elevada:
(i) se houver efeito negativo de inflação sobre produto, este é bastante pequeno;
(ii) parece haver um threshold abaixo do qual não há trade-off entre inflação e crescimento;
(iii) esse threshold parece ser mais alto para economias em desenvolvimento!
E agora?
Nesse momento em que inflação não é preocupação primária, esse post pode parecer meio fora de lugar. Mas acho que pode permitir uma discussão interessante sobre credibilidade do BC, bem como sobre nível de gasto compatível com uma taxa de inflação tolerada mais elevada.
Evidência 1: Nonlinear Effects of Inflation on Economic Growth, by Michael Sarel © 1996 International Monetary Fund.
This paper examines the possibility of nonlinear effects of inflation on economic growth. It finds evidence of a significant structural break in the function that relates economic growth to inflation. The break is estimated to occur when the inflation rate is 8 percent. Below that rate, inflation does not have any effect on growth, or it may even have a slightly positive effect. When the inflation rate is above 8 percent, however, the estimated effect of inflation on growth rates is significant, robust, and extremely powerful. The paper also demonstrates that when the existence of the structural break is ignored, the estimated effect of inflation on growth is biased by a factor of three.
Contra-Evidência 1: Warning: Inflation May Be Harmful to Your Growth, by Atish Ghosh and Steven Phillips © 1998 International Monetary Fund.
While few doubt that very high inflation is bad for growth, there is less agreement about the effects of moderate inflation. Using panel regressions and allowing for a nonlinear specification, this paper finds a statistically and economically significant negative relationship between inflation and growth, which holds robustly at all but the lowest inflation rates. A "decision-tree" technique identifies inflation as one of the most important determinants of growth. Finally, short-run growth costs of disinflation are only relevant for the most severe disinflations, or when the initial inflation rate is well within the single-digit range.
Evidência 2: Threshold Effects in the Relationship Between Inflation and Growth, by Mohsin S. Khan and Abdelhak Senhadji 2000 © International Monetary Fund (IMF)
This paper reexamines the issue of the existence of threshold effects in the relationship between inflation and growth, using new econometric techniques that provide appropriate procedures for estimation and inference. The threshold level of inflation above which inflation significantly slows growth is estimated at 1-3 percent for industrial countries and 7-11 percent for developing countries. The negative and significant relationship between inflation and growth, for inflation rates above the threshold level, is quite robust with respect to the estimation method, perturbations in the location of the threshold level, the exclusion of high-inflation observations, data frequency, and alternative specifications.
Evidência 3, mais atual: Barro (2001) "Handbook of monetary and fiscal policy"
Utiliza variáveis instrumentais para dar conta da endogeneidade da inflação, encontrando efeito significativo e negativo sobre crescimento, mas de magnitude bastante reduzida: um aumento de 10 pontos percentuais da inflação reduziriam o PIB em 0.2% ao ano, em média.
Resumo da ópera: A despeito da contra-evidência 1, parece haver emergido relativo consenso de que, excetuando-se episódios de inflação realmente elevada:
(i) se houver efeito negativo de inflação sobre produto, este é bastante pequeno;
(ii) parece haver um threshold abaixo do qual não há trade-off entre inflação e crescimento;
(iii) esse threshold parece ser mais alto para economias em desenvolvimento!
E agora?
