Organic composition of capital

The organic composition of capital (OCC) is a concept created by Karl Marx in his theory of capitalism, which was simultaneously his critique of the political economy of his time. It is derived from his more basic concepts of 'value composition of capital' and 'technical composition of capital'. Marx defines the organic composition of capital as "the value-composition of capital, in so far as it is determined by its technical composition and mirrors the changes of the latter". The 'technical composition of capital' measures the relation between the elements of constant capital (plant, equipment and materials) and variable capital (wage workers). It is 'technical' because no valuation is here involved. In contrast, the 'value composition of capital' is the ratio between the value of the elements of constant capital involved in production and the value of the labor. Marx found that the special concept of 'organic composition of capital' was sometimes useful in analysis, since it assumes that the relative values of all the elements of capital are constant. In Book I of Capital, Marx made the simplifying assumption that all valuation was in terms of what is often called labor-values (and he called 'values'). In Book III, however, he states that equilibrium values between industries could not be directly proportional to their labor content. The latter only determined equilibrium values in his pre-capitalist 'Simple Commodity Production', where the producers owned their means of production and natural resources were used freely. In Book III, first he assumed that land could be used freely and showed that the equilibrium prices were his 'prices of production'. Later, when he introduced land ownership and the rent on land, the equilibrium prices were to be 'modified production prices' that took the rent of land into account. The implication of this is that the valuation used for the 'value composition of capital' had to be accordingly modified, since the labor-values used throughout Book I was an expedient he used in order to not excessively complicate the communication of this theory.