Typically the planning authorities also collected comprehensive data on the physical units of products produced.
They were influenced by the ideas Karl Marx had about the creation and accumulation of wealth, and about productive and unproductive labour in capitalist society.
[3] Critics of MPS accounts argue that by providing a lot of detail about the value and physical quantity of tangible products produced, but very little detail about those who depended on that production as consumers, how income, consumer items and capital wealth were truly distributed in the USSR.
However, supporters of the system argued that, if many goods and services are supplied to ordinary consumers free of charge, or below cost (a "socialized" component of household income) then valuing consumption expenditures in money prices becomes both difficult and rather meaningless.
In that case, it is argued, a more appropriate strategy is to measure what physical goods and services people actually consume, and to what benefits they are entitled.