Competition agency guidelines, policy statements and related advocacy activities are an important vehicle for policy expression across the full spectrum of anti-competitive practices and for the guidance of firms in determining their market conduct. They are also, often, a revealing window into the thinking of agency officials and professional staff regarding the problems they are grappling with, thus providing an empirical foundation for mapping the trends and evolution of such policy thinking across diverse jurisdictions and over time. An early, influential example of such guidelines was the Merger Guidelines adopted by the US Department of Justice in 1968,1 which embodied and set out clearly the structure-conduct-performance paradigm of industrial organization and competition policy analysis that was prevalent at the time.