Socialism is a post-commodity economic system, meaning that production is carried out to directly produce use-value (to directly satisfy human needs, or economic demands) as opposed to being produced with a view to generating a profit. The stage in which the accumulation of capital was viable and effective is rendered insufficient at the socialist stage of social and economic development, leading to a situation where production is carried out independently of capital accumulation in a supposedly planned fashion. Although Karl Marx and Friedrich Engels understood planning to involve the input and decisions of the individuals involved at localized levels of production and consumption, planning has been interpreted to mean centralized planning by Marxist-Leninists during the 20th century.