Academic

• 2005 Colorado Academic Library Impact Study
• Library Impact Data Project: Looking for the Link Between Library Usage and Student Attainment
• The Value of Academic Libraries (Association of College and Research Libraries)

K12

• How Pennsylvania School Libraries Pay Off: Investments in Student Achievement and Academic Standards
• Informational Brief: Impact of School Libraries on Student Achievement (New York Comprehensive Center)
• Latest Study: A full-time school librarian makes a critical difference in boosting student achievement
• Pennsylvania School Library Project (briefings)
• Research and statistics to help advocates make the case for libraries at every stage of youth development and education
• School Libraries Deliver 
• School Library Impact Studies (lists studies from 21 states plus Ontario)
• School Library Impact Studies Summary
• School library infographics: research and advocacy (Joyce Valenza) 
• School Libraries Work! 2008 (pdf - 304 kb)
• Student Learning Through Wisconsin School Library Media Centers (Wisconsin Department of Public Instruction)

Public

Statewide Library Services

• Cost Benefit: What iCONN Saves the State’s Libraries and Municipalities (Connecticut State Library)