Socialist economy in the context of "Democratic socialism"

A mixed economy is an economic system that includes both elements associated with capitalism, such as private businesses, and with socialism, such as nationalized government services.

More specifically, a mixed economy may be variously defined as an economic system blending elements of a market economy with elements of a planned economy, markets with state interventionism, or private enterprise with public enterprise. Common to all mixed economies is a combination of free-market principles and principles of socialism. Alternatively, a mixed economy can refer to a reformist transitionary phase to a socialist economy that allows a substantial role for private enterprise and contracting within a dominant economic framework of public ownership. This can extend to a Soviet-type planned economy that has been reformed to incorporate a greater role for markets in the allocation of factors of production.

Calculation in kind or calculation in-natura is a way of valuating resources and a system of accounting that uses disaggregated physical magnitudes as opposed to a common unit of calculation. As the basis for a socialist economy, it was proposed to replace money and financial calculation. In an in-kind economy, products are produced for their use values (their utility) and accounted in physical terms. By contrast, in money-based economies, commodities are produced for their exchange value and accounted in monetary terms.

Calculation in kind would quantify the utility of an object directly without recourse to a general unit of calculation. This differs from other proposed methods of socialist calculation, such as Taylor-Lange accounting prices, and the use of labor time as a measure of cost.

The Lange model (or Lange–Lerner theorem) is a neoclassical economic model for a hypothetical socialist economy based on public ownership of the means of production and a trial-and-error approach to determining output targets and achieving economic equilibrium and Pareto efficiency. In this model, the state owns non-labor factors of production, and market simulations are used by the planning organs to allocate final goods and consumer goods. The Lange model states that if all production is performed by a public body such as a democratic state, and there is a functioning price mechanism, this economy will be Pareto-efficient, like a hypothetical market economy under perfect competition. Unlike models of capitalism, the Lange model is based on direct allocation, by directing enterprise managers to set price equal to marginal cost in order to achieve Pareto efficiency. By contrast, in a capitalist economy, private owners seek to maximize profits, while competitive pressures are relied on to indirectly lower the price; this discourages production with high marginal cost and encourages economies of scale.

This model was first proposed by Oskar R. Lange in 1936 during the socialist calculation debate, and was expanded by economists like H. D. Dickinson and Abba P. Lerner. Although Lange and Lerner called it "market socialism", the Lange model is a form of centrally planned economy where a central planning board allocates investment and capital goods, while markets allocate labor and consumer goods. The planning board simulates a market in capital goods by a trial-and-error process first elaborated by Vilfredo Pareto and Léon Walras. The Lange Model is in practice a type of centrally planned economy and not a type of market socialism.