The Material Flow Accounts (CFM) show the physical inputs that enter the economy from the environment or other economic systems and the outputs that are heading towards other economies or the natural environment. Therefore, it describes the interaction of an economy with the environments and with economies from the rest of the world. In this way we can determine the dependencies and deficiencies of an economic system and, at the same time, the impacts that it generates on the environment.

The CFM form part of the System of Environmental-Economic Accounting adopted by the UN and are consistent with national economic accounts, as they use similar concepts and accounting standards that allow them to obtain a set of aggregated indicators on the use of natural resources.

Idescat produces annual statistics adapting for Catalonia the harmonised methodology, which is defined and recommended by Eurostat.

The concepts included in the CFM are expressed in tons and are the following:

Domestic extraction
Physical trade of materials
Domestic processed output
Direct input of materials
Domestic consumption of materials
Relating the physical and monetary indicators, for example the GDP, allows us to calculate indicators of efficiency in the use of natural resources. The main efficiency indicators are material productivity, which is the result of dividing the GDP by the domestic consumption of materials and the material intensity, which is the opposite.