MONTREAL — Signs of the American economy's perilous condition are everywhere — from yawning fiscal and current-account deficits to plummeting home prices and a feeble dollar.

But something that shows up in none of the economic indicators may be driving many of them: the deterioration of American management, which is undermining not only many of America's great enterprises, but also its legendary spirit of enterprise.

Paradoxically, one indicator that has been improving steadily in the United States — productivity — may be the clearest sign of the problem. When it comes to productivity, managers either invest in employee training, more efficient manufacturing processes and the like, or they take steps that appear to boost productivity in the short run but that erode it in the long run.