Stadial (stage-based) theory clarifies the relation between the evolving conception of mature socialism, on the one hand, and historical experiences of central planning and "market socialism," on the other. The core of mature socialism is a system of multilevel democratic iterative coordination (MDIC), involving mutually supportive and mutually defining roles for a central authority and enterprises. This conception clarifies the relations between the socialist core and various precursor forms in existing transitional societies.