Artificial intelligence (AI) is reshaping economies, promising to generate productivity gains, improve efficiency and lower costs. At the same time, AI is also fuelling anxieties and ethical concerns. As AI’s impacts permeate our societies, its transformational power must be put at the service of people and the planet. This document presents the work conducted by the Expert Group on Artificial Intelligence at the OECD (AIGO) to scope principles to foster trust in and adoption of AI. In particular, this paper presents a common understanding of what is an AI system as well as a framework that details the stages of the AI system lifecycle. This work informed the draft Recommendation of the Council on Artificial Intelligence. On 22 May 2019, the OECD Council adopted the Recommendation – also referred to as the OECD AI Principles – at the Ministerial level.