The measurement of the non-observed economy (NOE) aims to offer an assessment for all those economic activities that cannot be observed directly from the information available in statistical organizations, in a manner compatible with the data estimated in National Accounts, within the framework of ESA 2010 (European System of Accounts).

Specifically, NOE refers to underground activities, i.e. those legal productive activities that are intentionally hidden from public authorities; illegal activities, informal activities and those carried out by households for their own final use; also those not observed due to statistical deficiencies.