WHILE Europe's austerity-minded governments and inflation-averse central bank must take much of the credit for the euro area's current economic problems, the crisis has been fanned by failures of regulatory reform and integration that have made adjustment much harder than it needs to be. Those failures also operated prior to the crisis, contributing to growth in imbalances, and without much more in the way of structural reform they will continue to be an economic albatross when the crisis is finally put to rest.

This week's Free exchange column looks at an underappreciated way in which regulatory burdens and incomplete integration have prevented the euro area from taking full advantage of the size of its market and growing richer: by constraining the growth of its cities:

Although America and the euro zone have similar total populations, America’s 50 largest metropolitan areas are home to 164m people, compared with just 102m in the euro area. This striking disparity has big consequences.

Differences in metropolitan populations may help explain gaps in productivity and incomes. Western Europe’s per-person GDP is 72% of America’s, on a purchasing-power-parity basis. A recent study by the McKinsey Global Institute, the consultancy’s research arm, reckons that some three-quarters of this gap can be chalked up to Europe’s relatively diminutive cities. More Americans than Europeans live in big cities: there is a particular divergence in the size of each region’s “middleweight” cities, those that teem just a little less than the likes of New York and Paris (see chart). And the premium earned by Americans in large cities relative to those in the countryside is larger than that earned by urban Europeans.

In highly skilled societies, bigger cities are associated with higher levels of productivity and income, the column explains. This seems to be due to the ways in which cities facilitate innovation in an age of rapidly increasing economic and technological complexity. Prosperity now requires lots of skilled individuals in reasonably close proximity to each other, to learn from and occasionally partner with as part of the process of coming up with and spreading new ideas. America appears to be better able than Europe to accomplish this across a wide range of places. 

But why? The piece explains:

Regulatory barriers to growth may be to blame. Tight zoning rules limit housing supply and raise prices by driving a wedge between construction costs and market prices. This “regulatory tax” amounts to over 300% in the office markets in Frankfurt, Paris and Milan, according to a 2008 study by Paul Cheshire and Christian Hilber of the London School of Economics, but is just 50% in Manhattan and, in effect, zero in fast-growing places like Houston. Taxes that add to transaction costs also help explain low European mobility.

Comparatively smaller cities also reflect incomplete European integration. Paris is large by national standards, for instance, accounting for around 30% of French GDP and boasting incomes per person some 59% above the western European average. But if there was genuine freedom of movement within Europe, big-city wage premiums should trigger a flood of migrants from outside national borders. There are linguistic barriers in the way, of course, but other obstacles, like the portability of pensions and the recognition of professional qualifications, make it even harder for Europe to match America’s urban jungles.

Language and cultural differences are obstacles to intra-euro-area migration, but Europeans are also move less across regions within individual countries than Americans do across state lines. And even if Europeans did become more mobile, they'd often be discouraged from moving to larger places thanks to the high cost of real estate.

Reform of these obstacles wouldn't immediately spark growth and lead the euro area out of recession. But they would help with fiscal crisis by buoying long-run growth prospects. Certainly clearing away such rules would make a great deal more sense as part of current reform packages than a continued focus on mostly counterproductive short-term austerity.