How does debt affect growth? The well-known correlation found by Rheinhart and Rogoff in their analyses of financial crises found that growth tends to substantially slow down as the debt to GDP ratio approaches 90%. Based on this correlation, policy makers began to advocate austerity as a way to reduce debt, and thereby restore growth.
Of course, correlation does not prove causation, and Paul Krugman jumped at that, pointing out that it was quite likely that causation ran the other way. As a result of anemic growth, countries would pursue countercyclical fiscal policy. This would create the appearance that only low growth countries pursue higher levels of debt. However, the association between the two variables actually arises from textbook countercyclical fiscal policy. Had the government decided to retrench, the economy would have suffered even more, compounding the growth problem.
So how to resolve these issues? A recent VoxEU article on the relationship between debt and growth caught my eye, as it proposed a novel mechanism to estimate the effect of debt on growth. While I don't understand the full mechanics, the working paper seems to use the stock of foreign debt as a variable to instrument the stock of debt. At the end of the analysis, the authors conclude that, while R+R find a strong correlation, the new data instrumented for endogenity cannot reject the null hypothesis that debt has no effect on growth. This then has a critical role in determining policy because it suggests that countries, when in dire output straits, should not ignore the role of fiscal policy. The debt effects are unlikely to be strong enough to overwhelm any first order effects from fiscal stimulus. Especially given the recent interest in hysteresis and reductions in potential output, it seems almost certain that fiscal retrenchment is not the answer. Along these lines, I also found some older articles, one an old study looking at old U.S. time series data, and another on Latin American growth, that both suggest we should be worry about the output gap. Long run growth can be seriously affected by temporary deviations, and therefore we need to fill the gap, whether by fiscal or monetary policy.
Another note in the paper that was particularly interesting was that the authors traced much of the negative correlation between debt and growth to the destructive policies governments would pursue when at high levels of debt. In the words of the authors:
We believe that there is a subtle channel through which high levels of public debt can have a negative effect on growth. In the presence of multiple equilibria, a fully solvent government with a high level of debt may decide to put in place restrictive fiscal policies aimed at reducing the probability that a change in investors’ sentiments would push the country towards the bad equilibrium. These policies, in turn, may reduce growth (Perotti 2012), especially if implemented during a recession (such policies may even be self-defeating and increase the debt-to-GDP ratio, DeLong and Summers 2012, UNCTAD 2011).3 In this case, it would be true that debt reduces growth, but only because high debt leads to panic and contractionary policies.This argument piqued my interest for two key reasons. The first is that it echoes a paper by Bernanke on the effect of supply shocks on the economy. In the paper, Bernanke argued that a lot of the damage from a supply shock wasn't actually from the shock itself, but rather from the monetary policy response. In the case of debt, much of the harm from high levels of debt isn't from the debt, but rather from the fiscal policy response.
The second is that this advice on debt and growth seems particularly pertinent for the Eurozone. This paper provides strong evidence that the austerity cure is anything but. Even if growth is needed, but fiscal retrenchment is not the answer. Netherland's recent rejection of harsh cuts, and France's electoral shift both show that democracy is having its say and is refusing this cup of self-defeating suffering. They recognize that cutting budgets cannot be the only way forward, and that policy needs to be fundamentally changed to recognize the elaborate chicken and egg relationship between debt and fiscal policy. I only hope that they figure out that omelet before the bond markets take away the chance.