Introduction: reflections on the state of the art of comparative economics / Andrew Zimbalist -- The evaluation of centrally planned economic systems / David Conn -- Some observations on inter-system comparisons / Alec Nove -- Is market socialism efficient? / Deborah Duff Milenkovitch -- Dynamic comparative economics / Ruud Knaack -- Central physical planning incentives and job rights / David Granick -- Incentives and elicitation schemes / Sian Koont, Andrew Zimbalist