One view, popular among economic historians, is that it takes time for the productivity-enhancing effects of new technologies to show up. Indeed, when radical innovations are first rolled out, their immediate effect is to reduce, not raise, productivity.
一种极受经济史学家欢迎的观点认为，新技术对生产力的提升作用是需要时间来逐步展现的。事实上，当那些开创性创新首次推出的时候，其直接效果是降低而非提高生产率。根据斯坦福大学知名经济史学家保罗·戴维（Paul David）的研究，当年作为新技术的电力就是个典型的例子。