The Quarterly Economic Accounts operation anticipates the data of the Economic Accounts of the Basque Country via the auxiliary information of quarterly-observed situational economic indicators. This information is modelled to obtain the quarterly estimate of the main macro-figures of the Basque economy in terms of Supply, Demand and Employment The real quarterly evolution of the GDP of the community and its provinces is thus determined. The concepts and definitions of the operation are established in the European System of Accounts.