Project preparation is a critical enabler of infrastructure development and has been identified as a key pillar in the G20 s strategic roadmap to develop infrastructure as an asset class. The reference tool will be a useful aid for policy-makers and practitioners in their quest to improve project preparation practices and their capacity for preparing quality infrastructure projects, building upon the G20 Principles for the Infrastructure Project Preparation Phase. The tool seeks to help address challenges faced by governments in early-stage project preparation through providing guidance in the areas outlined below.