While governments throughout the world have different approaches to how they make their public sector information (PSI) available and the terms under which the information may be reused, there appears to be a broad recognition of the importance of digital networks and PSI to the economy and to society. However, despite the huge investments in PSI and the even larger estimated effects, surprisingly little is known about the costs and benefits of different information policies on the information society and the knowledge economy.By understanding the strengths and weaknesses of the current assessment methods and their underlying criteria, it should be possible to improve and apply such tools to help rationalize the policies and to clarify the role of the internet in disseminating PSI. This in turn can help promote the efficiency and effectiveness of PSI investments and management, and to improve their downstream economic and social results. The workshop that is summarized in this volume was intended to review the state of the art in assessment methods and to improve the understanding of what is known and what needs to be known about the effects of PSI activities.