This Guidance Note is one of several developed by CoST – on its core features. This Note focusses on the feature of the Independent Review, known previously as ‘assurance’ – the validation and interpretation of data disclosed on infrastructure projects. The independent review translates complex data into clear and compelling information so that key stakeholders can put this information in the public domain and enhance accountability. The Note supplements a more detailed Independent Review Manual (Volume 1 and 2) both of which are primarily aimed at CoST members and Independent Review Teams/Professionals, but which can provide useful lessons for similar initiatives and other advocates of infrastructure transparency.