What is the evidence available on the effects of currency depreciation on the current account balance or the trade balance?

Some economists have recently argued that currency devaluations or depreciations have lost their ability to improve the current account balance or trade balance of the industrialized economies. The magazine The Economist, for example, observes that “devaluations do not seem to have provided quite the same boost [to exports] recently.” What is the evidence available on the effects of currency depreciation on the current account balance or the trade balance? Is the Economist correct? Please explain.