Is the United States Becoming Less of an Optimal Currency Area?

It took the United States roughly 150 years to become an optimal currency area (OCA), according to economic historian Hugh Rockoff. This long journey meant that it was not until the late 1930s that a one-size-fits-all monetary policy made sense for the U.S. economy. Since then the U.S. economy has often been held up as the best example of a currency union that meets the OCA criteria. This especially was the case when comparisons have been made to the Eurozone, like in this classic Blanchard and Katz (1992) paper.  But all is not well in this land of the OCA.

Declining Labor Mobility

Since the 1980s there has been a decline in labor mobility across the United States.  This can be see in the figure below:

Source: Molloy, Smith, and Wozniak (2014)

A number of explanations have been given for this decline, but in my view the best one is found in David Schleicher's paper titled "Stuck! The Law and Economics of Residential Stability". Schleicher makes the case that land-use regulations, occupational licensing, non-compete clauses, and other regulations are making it harder for individuals to pick-up and move to better jobs.  A spate of recent news stories reinforces how consequential the these labor market constraints are for many people. Schleicher notes that they are particularly onerous for those individuals that need to move the most, the folks from lower socioeconomic groups most affected by regional economic shocks. 

The recent Autor et al. papers on the China shock vividly illustrate this point. On the surface these papers speak to how big and persistent the China shock was on certain local U.S. economies. But their deeper finding, in my view, is that they point to declining labor mobility in the United States. For they show the China shock had little effect on local population flows in the affected communities. That is, the unemployed in the affected regions did not readily move away to jobs elsewhere. 

The above papers are consistent with a recent IMF study that revisited the Blanchard and Katz (1992) paper and concluded the following (my bold):

[A] given regional shock has triggered less interstate net migration, and a larger response of regional unemployment and participation in the short-run. That is, following the same negative shock to labor demand, affected workers have more and more tended to either drop out of the labor force or remain unemployed instead of relocate...

Tyler Cowen's new book, The Complacent Class, also speaks to this development. His argument is that U.S. culture has become increasingly risk averse. The higher risk aversion explains the growth of the labor market constraints listed in the Schleichner paper as well as the declining desire to pick up and move to better opportunities.

Implications for the United States as an OCA

So why does the decline in labor mobility matter for the U.S. economy? To answer this question, recall that the Fed is doing a one-size-fits-all monetary policy for fifty different state economies. That is, the Fed is applying the same monetary conditions to states that often have very different economies, both structurally and cyclically. For example, Michigan and Texas have had very different trajectories for their economies. Does it really makes sense for them both to get the same monetary policy? 

According to the OCA, the answer is yes under certain circumstances. The OCA says it makes sense for regional economies to share a common monetary policy if they (1) share similar business cycles or (2) have in place economic shock absorbers such as fiscal transfers, labor mobility, and flexible prices. If (1) is true then a one-size-fits-all monetary policy is obviously reasonable. If (2) is true a regional economy can be on a different business cycle than the rest of currency union and still do okay inside it. The shock absorbers ease the pain of a central bank applying the wrong monetary policy to the regional economy. 

For example, assume Michigan is in a slump and the Fed tightens because the rest of the U.S. economy is overheating. Michigan can cope with the tightening via fiscal transfers (e.g. unemployment insurance), labor mobility (e.g. people leave Michigan for Texas), and flexible prices (workers take a pay cut and are rehired). 

To be clear, a regional economy is not making a discrete choice between (1) and (2) but more of a trade off between them. Michigan, for example, can afford to have its economy a little less correlated with the U.S. economy if its shock absorbers are growing and vice versa. There is a continuum of trade offs that constitutes a threshold where it makes sense for a regional economy to be a part of a currency union. That threshold is the OCA frontier in the figure below: 

Circling back to the original OCA question, the decline in labor mobility documented above matters because it means that certain regions in the United States are becoming less resilient to shocks.This is especially poignant given the findings in Blanchard and Katz (1992) that interstate labor mobility has been the main shock absorber for regional shocks. Consequently, monetary policy shocks may prove to be more painful than before for some states. Unless increased fiscal transfers and price flexibility make up for the decline in labor mobility, the implication is clear: the U.S. is gradually moving away from being an OCA.

As it turns out, I have a 2010 paper in the Journal of Macroeconomics where I examined whether the U.S. economy is an OCA. Looking at state data for the Great Moderation period, I concluded that there might have been some gain for the Rust and Energy Belts regions having their own currency during this period. There also would have been additional costs so I do not actually endorse the break up of the dollar zone in the article. However, what is interesting in retrospect is that period I examined in the article coincides with the decline in interstate labor mobility. It is no coincidence, then, that I got the results I did.

The policy implications seem clear. Policy makers at the local, state, and federal level need to push policies that increase labor market mobility. There is a lot of work to do on this front, but it is important to do so to keep the United States an OCA. The Schleichner paper provides some suggestions and is good starting point for discussion.

Related Links
(1) I interviewed David Schleichner about his paper in a recent podcast.
(2) See Alex Tabarrok's take on the decline in labor mobility