New-Classical neutrality results have generated an enormous debate because they appear to have strong implications for policy. The author argues that irrelevance propositions are policy irrelevant. If these propositions are true, then behaving as if they are false has zero costs; but if they are...

Progress is better for some consumers than for others. The authors analyze the factors governing how much a consumer gains from progress, defined as price declines and the introduction of new and improved products, and they show how these factors vary systematically across consumer groups....