Choosing legal rules or standards in antitrust enforcement: a proposal for extending and facilitating the use of the decision-theoretic approach

The choice of legal standards (LSs) in antitrust enforcement, to guide the assessment of potentially anticompetitive conduct, in order to decide whether there is liability or not, has been hotly debated for many years. The debate has gained in intensity in recent years as a result of the concerns expressed in many countries with the antitrust treatment of the major digital platforms. This article provides a detailed presentation of a new methodology for defining LSs along the continuum of LSs, depending on the screens assessed at different stages of the continuum. This is followed by a detailed formal examination of how all the pertinent factors that could influence error minimisation interact to determine the optimal LSs for different conducts and markets. The framework can be used to examine how the choice of error minimising LSs depends on the context in which specific conduct types are undertaken.