The data hold more surprises. Here are a few:
- Even though the US Constitution assigns power over the budget (and most other economic powers) to Congress, not to the president, there is no difference in growth rates depending on which party controls Congress. It’s the presidency that matters.
- The Democratic growth advantage is concentrated in the first two years of a presidency, especially the first, even though Republicans bequeath much slower-growing economies to Democrats and US GDP growth is positively serially correlated (ρ ≈ 0.40 in quarterly data).
- As indicated both by time series models and by genuine ex ante forecasts, Democrats do not inherit economies that are poised for more rapid growth. Granger-causality runs from party-to-growth not from growth-to-party.
Trying to explain the partisan growth gap
Confronted with such stark partisan differences, a macroeconomist naturally wonders whether the explanation could be that fiscal policy was, on average, more expansionary under Democrats. We assess this possibility in a variety of ways and come up with the same answer: no. What about monetary policy, despite the Federal Reserve’s vaunted independence from politics? The answer here is that, if anything, monetary policy was more pro-growth under Republican presidents.4
If the partisan gap cannot be explained by differential monetary and fiscal policy, what does explain it? And do these explanatory factors suggest it was good luck or good policy? We searched over a wide variety of factors, mostly entered in the form of econometric ‘shocks’, that is, as residuals from regressions that include the variable’s own lags and the current and lagged values of GDP growth. Four showed econometric promise:5
- Oil price shocks;
- Total factor productivity (TFP) shocks, adjusted to remove cyclical influences;
- Foreign (that is, European) growth shocks;
- Shocks to consumer expectations of future economic conditions.
In addition, defence spending shocks mattered in samples that include the Korean War, but not much in samples that do not. Using all five of these variables enables us to explain about half of the partisan gap in GDP growth rates since 1947.
As we peruse the list of explanatory variables, the first (oil shocks) looks to be mainly good luck, although US foreign policy (rather than economic policy) certainly played a role. (Think about George W Bush’s invasion of Iraq, for example.) The second variable (TFP) should in principle measure improvements in technology – and so be mostly driven by luck. But a wide variety of economic policies, ranging from R&D spending to regulation and much else, might influence TFP in multiple, subtle ways. And TFP shocks affect the economy with long lags, so that a portion of the TFP-induced strong growth for Democrats was inherited from previous administrations. The third (real growth in Europe) should not have much to do with US economic policies. And when you couple the fourth variable (consumer expectations) with the observed fact that spending on consumer durables grows much faster under Democrats, you get a tantalising suggestion of a self-fulfilling prophecy – consumers, expecting faster growth under Democratic presidents, buy more durable goods on that belief, which makes the economy grow faster. Did they know something economists didn’t?6
These findings raise a host of questions. Among them:
- Is the basic finding limited to post-World War II data?
We think not. We found a similar (though smaller) partisan growth gap in US data going all the way back to 1875. But the 1875–1947 data are dominated by the administration of Franklin D Roosevelt, during which real GDP grew at a heady 7.4% annual rate.
- Are there similar partisan gaps in other countries?
We looked briefly at four other large democracies with stable two-party systems: Canada, the UK, France, and Germany. The Canadian data display a similar (though not quite as large) GDP growth gap in favour of Liberal over Conservative prime ministers. But that is not true in any of the three European countries.
Our best econometric efforts explained little more than half of the Democratic growth gap - our ‘glass’ wound up literally half full and half empty. What factors explain the rest? Hopefully, further research will cast some light on that question.
Alberto Alesina and Jeffrey Sachs (1988), “Political Parties and the Business Cycle in the United States, 1948–1984”, Journal of Money, Credit, and Banking, 20(1): 63–82.
Larry M Bartels (2008), Unequal Democracy: The Political Economy of the New Gilded Age, New York: Russell Sage Foundation, and Princeton, NJ: Princeton University Press.
Alan S Blinder and Mark W Watson (2014), “Presidents and the U.S. Economy: An Econometric Exploration”, NBER Working Paper 20324, July.
Michael Comiskey and Lawrence C Marsh (2012), “Presidents, Parties, and the Business Cycle, 1949–2009”, Presidential Studies Quarterly, 42(1): 40–59.
Ray C Fair (2011), Predicting Presidential Elections and Other Things, Second Edition, Stanford, CA: Stanford University Press.
1 Alesina and Sachs (1988), Bartels (2008, Chapter 2), and Comiskey and Marsh (2012) are a few exceptions. There are not many.
2 In Blinder and Watson (2014), we compute standard errors in a variety of ways and find that the partisan gap is statistically significant at roughly a 1% significance level.
3 But the Carter-to-Reagan transition exhibits only a small slowdown.
4 This is true even though growth was decidedly faster under Fed chairmen who were first appointed by Democrats.
5 We omit from this list factors that we found help explain why Republican presidents should have shown a growth advantage.
6 The partisan growth gap does not rely on recent data. In fact, the estimate generally increases as we shorten the sample by eliminating more recent data.