• Data reference period
• Geographic localization (Portugal)

• REFERENCE PERIOD:  Period to which the information refers and which may be a specific day or a time interval (month, fiscal year, calendar year, among others).
• DOMESTIC EXTRACTION:  All solid, liquid and gaseous materials (excluding water and air, but including the water content of materials) that are extracted from economic territory, to be used in production or consumption processes.
• RAW MATERIAL EQUIVALENTS :  Conversion factors used to express a unit of product traded into the amount of material extraction needed, anywhere in the world, to produce the traded product.
• RAW MATERIAL CONSUMPTION :  The amount of material in terms of Raw material equivalents (RME) needed to produce the products consumed in the geographical reference area.
• MATERIAL FOOTPRINT:  See RAW MATERIAL CONSUMPTION

Material footprint = Raw material equivalent of imports (RME_IM) + domestic extraction (DE) - raw material equivalents of exports (RME_EX)