According to Michael Ellman, in a centrally planned economy "the state owns the land and all other natural resources and all characteristics of the traditional model the enterprises and their productive assets. Collective ownership (e.g. the property of collective farms) also exists, but plays a subsidiary role, and is expected to be temporary." The private ownership of the means of production still exist, although it plays a fairly smaller role. Since the class struggle in capitalism is caused by the division between owners of the means of production and the workers who sell their labour, state ownership (defined as the property of the people in these systems) is considered as a tool to end the class struggle and empower the working class.