Another prominent economist, Harvard’s Lawrence Summers, has objected that this story is incompatible with a second recent trend, namely declining employment of men aged 25-54. If productivity has fallen temporarily because everyone is hard at work at the twenty-first-century equivalent of reorganizing the factory floor, then the employment rate should be going up, not down, as firms continue to operate their old “steam-powered machinery” at the same time they are adding new “electrical capacity.”