"Knowledge is one of the most scarce of all resources, so that one of the most important differences among alternative ways of organizing an economy is in how effectively they use what knowledge exists. In a market economy, it is not necessary that the innumerable decision-makers understand the costs entailed by their decisions. It is only necessary that they be confronted with those costs in the prices charged. In a “planned” economy, however, those who plan the production and distribution have to be able to understand and quantify the costs their decisions entail— a far more formidable task, if actually done, but a task that can be evaded with rhetoric or with estimates whose validity the public is usually unable to judge at the time, and which will usually be forgotten by the time the real costs become clear, often years later."