The Best Evidence of the Effect of Products Liability Law on the Accident Rate: Reply

Abstract

The differences between Professor Whitford's views and mine are of crucial importance to the law of products liability. Our objectives—indeed, the objectives of all interested in the field—are similar: to identify policies that, other things equal, will reduce the seriousness and frequency of injuries suffered by consumers. Professor Whitford and I differ sharply, however, in our predictions of the empirical effects of modern products liability policy. According to Professor Whitford, the policy adopted by courts over the last twenty years—the expansion of manufacturer liability beyond that undertaken in warranties—is likely to have reduced the rate of product defects. According to my investment theory, on the other hand, if consumer and manufacturer investments in safety are substitutes at the margin, the expansion of manufacturer liability is likely to have increased the rate of defects and the rate of consumer injuries. The vast number of product-related injuries compels us to examine these different implications very carefully. It is estimated that in 1977 alone, for example, consumers in the United States suffered 36 million product-related injuries. Professor Whitford's criticism of my article rests upon a misunderstanding of the nature of scientific reasoning. Whitford demands that my investment theory, as a "complete" theory, explain every phenomenon associated with product warranties and directly refute every conceivable alternative warranty theory. These requirements allow Whitford to confer significance upon his assortment of "partial" theories, though he presents no evidence supporting any of them, and to dismiss the investment theory, though he acknowledges the substantial evidence supporting it. Whitford's typology of theories is unique, and his standard of scientific proof is unrealistic. I know of no scientific theory that has ever met such a standard, and doubt that any theory ever will. More importantly, however, Whitford's methodological strategem diverts attention from the empirical issue dividing us that ought to be the central focus of product liability reform: whether there is evidence that consumer and manufacturer investments in optimizing productive services are substitutes over the range relevant to legal liability. The answer to this question and to this question alone will determine whether modern developments in products liability law have increased or decreased the rate of product defects and injuries.