With some of the conceptual background about productivity summa rized, we now turn to a discussion of the criteria for a good mea surement sys tem. Numerous au thors have discussed such criteria (e.g., Kendrick, 1977; Kopelman, 1986; Ma honey, 1988; Mali, 1978; Muckler, 1982; Pritchard, 1990b; Tuttle, 1981; Johnston, Brignall, & Fitzgerald, 2002; Salas, Burke, Fowlkes, & Priest, 2003). These criteria serve as comparison points for eval uating a productivity measurement sys tem, and will be used in a later chapter as the basis for evalu ating ProMES.