For the purposes of pricing, Project MUSE categorizes North American academic libraries into tiers based upon their placement in The Carnegie Classification of Institutions of Higher Education (2000 edition). This criterion was chosen because it represents, in essence, the level of research activity at an institution and its relation to the institution's mission. Because Canadian institutions are not classified by the Carnegie Foundation, these institutions have been "mapped" into the five pricing tiers based upon similar criteria related to research activity and educational mission.
For pricing journal collection subscriptions, each of the five tiers is further divided and into four quartiles based on usage. Usage is defined by the number of full-text downloads per institution during a calendar year, and quartiles are determined by comparing relative usage levels among institutions in the same tier.