There are numerous clinically based models for finding the “best evidence” for the diagnosis and treatment of disease. This process is called evidence-based medicine or EBM, which has been defined as "the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research”.¹ The need for improved access to high quality public health information has been echoed in various forums involving public health professionals, librarians, and information specialists since the mid 1990s.^2-6 The information needs of the public health workforce have become all the more urgent with the increasing frequency of emergence of new infectious diseases such as severe acute respiratory syndrome (SARS) and avian influenza, as well as the increasing concern about acts of bioterrorism, such as spreading anthrax spores via the US Postal Service in 2001.

A major difficulty in meeting these needs is the great breadth of the public health discipline that makes it difficult to identify and collect a body of evidence-based literature to address the growing multitude of specific public health information needs. The public health workforce may be more diverse than any other group of health professionals⁷ and includes professionals trained in dozens of disciplines,^{4, 6} ranging from environmental health to veterinary medicine, from sanitary engineering to epidemiology.

Access to evidence-based public health information has become a growing concern for medical librarians. In 1997, the National Library of Medicine (NLM) along with the Centers for Disease Control and Prevention (CDC), the Association of State and Territorial Health Officials (ASTHO), the National Association of County and City Health Officials (NACCHO), and other public health organizations formed the Partners in Information Access for the Public Health Workforce.⁸ The mission of Partners is to help the public health workforce find and use information effectively to improve and protect the public's health. The Evidence-Based Practice for Public Health Project at the Lamar Soutter Library, University of Massachusetts Medical School, was initiated in 2001. At the start of this project there was little attention paid to "best practices" for population-based public health. The overall purpose of this project was to address the need for access to quality evidence-based public health information.

In an effort to improve access to resources for evidence-based public health practice, the project has identified the knowledge domains of public health, public health journals and bibliographic databases, and evidence-based resources for public health practice. The project compared existing resources for locating, summarizing, synthesizing, and disseminating evidence-based information available to clinical medical practitioners with resources available to public health practitioners. We found that there were many more types of resources focused on clinical medical practice than on public health practice. The clinical medical resources were based on several different models of information search, summary, synthesis, and delivery, and some of most promising models had little or no presence in the public health arena. To explore and address this gap, the project sought to examine and classify the features of the clinical evidence-based medicine models, to assess their potential for improving access to evidence-based public health information, and to develop new models that could effectively address the unique needs of public health professionals.

The project team undertook a qualitative study to determine the information needs of public health practitioners and to develop strategies to improve access to credible and relevant information. The study combined three objectives that previous investigators had generally pursued individually: (1) the characterization of information needs of public health practitioners, (2) the assessment of barriers to information access, and (3) the identification of typical information seeking behaviors. We have used the insights gained from the study to inform the construction of an extended classification of the types of information needed by public health professionals and of an information system model that could meet their needs for access to diverse credible sources.