Should public policy respond to positional externalities?

A nice suit is one that compares favorably with those worn by others in the same local environment. More generally, a positional good is one whose utility depends strongly on how it compares with others in the same category.1 A positional externality occurs when new purchases alter the relevant context within which an existing positional good is evaluated.2 For example, if some job candidates begin wearing expensive custom-tailored suits, a side effect of their action is that other candidates become less likely to make favorable impressions on interviewers. From any individual job seeker's point of view, the best response might be to match the higher expenditures of others, lest her chances of landing the job fall. But this outcome may be inefficient, since when all spend more, each candidate's probability of success remains unchanged. All may agree that some form of collective restraint on expenditure would be useful. In such cases, however, it is often impractical to negotiate private solutions. Do positional externalities then become legitimate objects of public policy concern? In attempting to answer this question, I employ the classical libertarian criterion put forth by John Stuart Mill3, who wrote the state may not legitimately constrain any citizen's freedom of action except to prevent harm to others. I argue that many positional externalities appear to meet Mill's test, causing not just negative feelings but also large and tangible economic costs to others who are ill-equipped to avoid them. I also discuss an unintrusive policy remedy for positional externalities, one modeled after the use of effluent charges to curb environmental pollution. The paper is organized as follows. Section 1 notes the deep similarity between the conditions that give rise to positional arms races and those that give rise to conventional military arms races. Section 2 follows with a review of evidence concerning the strength of concerns about relative position. Section 3 describes some of the tangible economic costs that people experience as a result of positional externalities arising from such concerns. Section 4 takes up the question of whether collective action directed against positional externalities is consistent with respect for individual rights. Section 5 describes how a progressive consumption tax could neutralize many of the most costly effects of positional externalities.