The Quality Assurance Framework for Earth Observation (QA4EO) was established and endorsed by the Committee on Earth Observation Satellites as a direct response to a call from the Group on Earth Observations (GEO).

GEO had identified the requirement to establish an internationally harmonised Quality Assurance (QA) strategy to enable interoperability and quality assessment "at face value" of EO data. QA4EO encompasses a framework and set of ten key guidelines, derived from best practices and with example templates included to aid implementation. Each GEO stakeholder community is responsible for its own overall governance within the framework.

QA4EO provides guidance to enable individual organisations to document, in a consistent manner, the necessary evidence of compliance, thereby allowing those commissioning the work to assess its adequacy and "fitness for purpose". QA4EO-compliant processes would unequivocally assure data quality and would encourage harmonisation across the whole GEO community.

QA4EO has been endorsed by CEOS as a contribution to facilitate the GEO vision for a Global Earth Observation System of Systems (GEOSS). The aim of GEOSS is to deliver comprehensive and timely knowledge/information products worldwide to meet the needs of its nine "societal benefit areas". This can only be achieved through the synergistic use of data derived from a variety of sources (satellite, airborne and in situ) and the coordination of the resources and efforts of the GEO members.

To accomplish this vision, starting from a system of disparate systems that were built for a multitude of applications, requires the establishment of an internationally coordinated operational framework to facilitate interoperability and harmonisation.

The success of this framework, in terms of data, is dependent upon the successful implementation of two key principles:

1. Accessibility / Availability and
2. Suitability / Reliability

Success also requires effective communication of these principles to all stakeholders. To implement these principles in a harmonised manner, CEOS (the space arm of GEO), through discussion with calibration and validation experts from around the world, established QA4EO to facilitate interoperability of GEO systems.

QA4EO is based on the adoption of guiding principles, which are implemented through a set of key operational guidelines derived from best practices, for implementation by the GEO community. Although these guidelines were originally developed to meet the needs of the space community, they have been written with the aid of national metrology institutes of the UK and the USA and, where appropriate, are based on best practices of the wider non-EO community. They should therefore be readily adoptable by all GEO communities as a top level framework that can subsequently be translated and implemented to serve each specialist need.