Laws of Returns to Factors

The article is mainly expository in character and seeks to supplement the discussion in. the usual textbooks. It begins by distinguishing clearly between laws of returns to a factor and laws of returns to scale, explains the former and brings out why the proper way to state the law is in terms of marginal and not average physical product. It then explains why it is not quite proper to describe the laws of returns to a factor as a law of variable proportions.