obtained by deducting intermediate consumption from gross output. Thus gross value added is equal to net output. Net value added is obtained by deducting consumption of fixed capital (or depreciation charges) from gross value added. Net value added therefore equals gross wages, pre-tax profits net of depreciation, and indirect taxes less subsidies. Differences between Marxist and neoclassical accounting of value added A difference between Marxist theory and conventional national accounts concerns the interpretation of the distinction between new value created, transfers of value and conserved value, and of the definition of "production". For example, Marxist theory regards the "imputed rental value of owner-occupied housing" which is included in GDP as a fictitious entry; if the housing is owner-occupied, this housing cannot also yield real income from its market-based rental value at the same time. In the 1993 manual of the United Nations System of National Accounts (UNSNA), the concept of "imputed rental value of owner occupied housing" is explained as follows: "6.89. Heads of household who own the dwellings which the households occupy are formally treated as owners of unincorporated enterprises that produce housing services consumed by those same households. As well-organized markets for rented housing exist in most countries, the output of own-account housing services can be valued using the prices of the same kinds of services sold on the market in line with the general valuation rules adopted for goods or services produced on own account. In other words, the output of the housing services produced by owner-occupiers is valued at the estimated rental that a tenant would pay for the same accommodation, taking into account factors such as location, neighborhood amenities, etc. as well as the size and quality of the dwelling itself. The same figure is recorded under household final consumption expenditures." Marxist economists object to this accounting procedure on the ground that the monetary imputation made refers to a flow of income which does not exist, because most home owners do not rent out their homes if they are living in them. Another important difference concerns the treatment of property rents, land rents and real estate rents. In the Marxian interpretation, many of these rents, insofar as they are paid out of the sales of current output of production, constitute part of the new value created and part of the real cost structure of production. They should therefore be included in the valuation of the