The result is that unit labor costs, one measure of competitiveness between economies, fell in Germany while they were rising in other countries. Since the crisis, they have stabilized and even declined in many countries, but they are not close to making up the difference. German costs are not rising either.

That makes it much harder than it used to be for the rest of the countries in the euro zone to compete with Germany. Germans are correct when they say that it was mistakes made by the other countries — whether in allowing real estate bubbles in Spain and Ireland or borrowing too much and failing to enact structural reforms in Italy — that caused the problems. But the euro has become a straitjacket for troubled economies trying to recover.

For Germany, the problems of its neighbors have helped it compete against non-European exporters, like Japan and the United States. The value of the euro is set by markets, but it seems reasonable to think it is based on some sort of average condition in the euro zone. If Germany still had its own currency, it would no doubt be stronger than the euro is now.

The impact of currencies could be seen earlier this month on successive days when Nissan, the Japanese automaker, and Daimler, the German maker of Mercedes cars, announced profits. Nissan moaned about the yen, which makes it very difficult to make money exporting cars from Japan, while Daimler forecast strong earnings if the euro stays where it is. The euro has lost a third of its value against the yen since the credit crisis began.

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The O.E.C.D. report is worth reading for its explanation of labor policies that other countries should consider. In good times, many German workers work overtime but are not immediately paid for it. Those hours are credited to their account, and when times get rough they go on part time but are paid full-time wages, with the difference coming out of the account. Another government policy allows companies to reduce hours with the government making up two-thirds of the lost pay.

Those policies no doubt reduce hiring when times are good, but also hold down layoffs when times are bad.