This National Audit Office report highlights progress across government in fulfilling most of its initial commitments to promote the transparency of public information. However, government needs a better understanding of costs, benefits and use to assess whether transparency is meeting its objectives of increasing accountability, supporting service improvement and stimulating economic growth. The Government has significantly increased the amount and type of public sector information released. Twenty-three out of 25 commitments by central government, due by December 2011, had been met by that month. However, the assessment of value for money is underdeveloped. While the Cabinet Office has identified six types of potential benefits from open data, it is not yet using this framework to evaluate the success and value for money of its various transparency initiatives. The new Open Data Institute will have a role to improve evidence on economic and public service benefits of open data. Levels of public interest in the different types of information released vary. More than four-fifths of visitors to the Government website data.gov.uk leave the site immediately without accessing any further link. In some sectors, data that would better inform accountability or choice is either not held or not yet made available. The Government estimates that public data already contributes £16 billion annually to the UK economy. Despite announced new transparency commitments to stimulate additional economic growth, the ability to maximise economic growth from traded data is constrained by current arrangements to charge for data, and limited understanding of potential benefits.