This study is an attempt to re-examination of information value and it’s economic efficiency from the viewpoint of information science. This study focuses on the analysis of the considerable discussions about added value of information and cost-benefit analysis of information. This study shows that the researchs of information value or value-added information have dealt with the effect of information use and the measuring information efficiency concerns cost-benefit analysis of information services. A case study on ‘the national digital library program’ is also demonstrated as a pilot model for the cost-benifit analysis of information services.