Reinhart & Rogoff e a controversia a respeito do “Growth in a Time of Debt”...

Em dia de reunião e decisão do Copom, recomendo dar um tempo e ler o artigo abaixo, assim como o trabalho objeto da critica e resposta da Reinhart e do Rogoff e o comentário do Chris Cook no FT..


In 2010, two Harvard economists published an academic paper that seemed to speak to the world’s biggest policy question: should we cut public spending to control the deficit or use the state to rekindle economic growth? “Growth in a Time of Debt” by Carmen Reinhart and Kenneth Rogoff has served as an important intellectual bulwark in support of austerity policies in the US and Europe. But we have shown that several critical findings advanced in this paper are wrong. So do we need to rethink austerity economics more broadly?
The Reinhart-Rogoff research is best known for its result that, across a broad range of countries and historical periods, economic growth declines dramatically when a country’s level of public debt exceeds 90 per cent of gross domestic product.
In their work with a sample of 20 advanced economies over the postwar period, they report that average annual GDP growth ranges between about 3 per cent and 4 per cent when the ratio of public debt to GDP is below 90 per cent. But average growth collapses to -0.1 per cent when the ratio rises above a 90 per cent threshold.
In a new working paper, co-authored with Thomas Herndon, we found that these results were based on a series of data errors and unsupportable statistical techniques. For example, because of straightforward miscalculation and unconventional method of averaging data, a one-year experience in New Zealand in 1951, during which economic growth was -7.6 per cent and the public debt level was high, ends up exerting a big influence on their overall findings.
When we performed accurate recalculations using their dataset, we found that, when countries’ debt-to-GDP ratio exceeds 90 per cent, average growth is 2.2 per cent, not -0.1 per cent. We also found that the relationship between growth and public debt varies widely over time and between countries.
So what does this mean? Consider a situation in which a country is approaching the threshold of a 90 per cent public debt/GDP ratio. It is not accurate to assume that these countries are reaching a danger point where economic growth is likely to decline precipitously.
Rather, our corrected evidence shows that a country’s growth may be somewhat slower once it moves past the 90 per cent public debt-to-GDP level. But we cannot count on this being true under all, or even most, circumstances. Are we considering the US demobilisation after the second world war or New Zealand experiencing a severe one-year recession? Our evidence shows that one needs to ask these and similar questions, including whether slow growth was the cause or consequence of higher public debt, before we can draw meaningful conclusions.
What about our present circumstances? Using Prof Reinhart’s and Prof Rogoff’s data, we found that for the years 2000 to 2009, the average GDP growth rate for countries carrying public debt levels greater than 90 per cent of GDP was either comparable to or higher than those for countries whose public debt/GDP ratios ranged between 30 and 90 per cent.
Of course, one could say that these were special circumstances due to the 2007-9 financial collapse and Great Recession. Yet that is exactly the point. When the US and Europe were hit by the financial crisis and subsequent collapse of private wealth and spending, deficit-financed government spending was the most effective tool for injecting demand back into the economy. The increases in government deficits and debt were indeed historically large in these years. But this was a consequence of the crisis and a policy tool for moving economies out of the deep recession. The high levels of public debt were certainly not the cause of the growth collapse.
The case for austerity has never relied entirely on Prof Reinhart and Prof Rogoff. But the other major claims made recently by austerity hawks have also not held up well. Focusing on the US case, austerity supporters circa 2009-10 consistently argued (frequently in this newspaper) that the large US deficits would lead to dangerously high inflation and interest rates. Neither of these predictions came true. In fact, both inflation and the interest rates on US Treasuries were at historic lows in the four years, 2009-12, during which government deficits were at their peak.
It is also not true that the large deficits have created an unsustainable burden on US government finances. In fact, since 2009, the US government’s interest payments on debt have been at historically low levels, not historic highs, despite the government’s rising level of indebtedness. This is precisely because the US Treasury has been able to borrow at low rates throughout these high deficit years.
We are not suggesting that governments should be free to borrow and spend profligately. But government deficit spending, pursued judiciously, remains the single most effective tool we have to fight against mass unemployment caused by severe recessions. Recent research by Prof Reinhart and Prof Rogoff, along with all related arguments by austerity proponents, does nothing to contradict this fundamental point.

Robert Pollin and Michael Ash, University of Massachusetts Amherst.

Fonte: FT