Quantitative information about economic activity and institutions provides the essential basis for economic inference. Its systematic collection in the form of economic statistics had its origin in the realisation that it is indispensable to the practice of economic management, the need for which became evident in the course of the Great Depression of the 1930s. The collection, collation and publication of national economic statistics is usually the responsibility of independent government agencies, and national statistics are aggregated and collated by various international agencies.
Economic statistics are collected according to a defined framework of arbitrary definitions and categorisations, the interpretation of which requires the exercise of professional judgement; and the same is true of their collation and aggregation. The consequential presence of a judgmental component in the published figures places a limit upon their accuracy and consistency, as a result of which importance is attached to the impartiality of the authorities responsible for their publication.