The projects in this proposal are part of a series of studies seeking ways to develop and harness search strategies ("hedges") that will improve retrieval of clinically relevant and scientifically sound reports from large, general purpose, biomedical research bibliographic databases such as MEDLINE. The purpose of the search strategies is 1) to assist health care providers to do their own searches; 2) to help reviewers of published evidence about managing health care problems to retrieve all relevant citations; 3) to provide resources for librarians to help clinicians construct their own searches; and 4) to provide input to bibliographic database producers about indexing processes and organization of databases. Our long-term objective is to harness the most clinically relevant content of electronic bibliographic databases so that their influence on clinical practice can be enhanced. We believe that improved search strategies are urgently needed given the inherent problems of indexing and retrieval in large databases, and the widespread and rapidly increasing direct use of these databases by clinicians, researchers, educators, administrators, lawyers, journalists, patients, and the general public, whose interests are primarily directed towards a small subset of the literature that is of most relevance to the cause, course, diagnosis, costs, prevention, and treatment of health care problems. The questions to be addressed in this proposal are related to defining journal subsets which may lead to better precision when searching in MEDLINE; investigating the accuracy and consistency of MEDLINE indexing; determining if retrieval is enhanced when searching in journal subsets that publish structured abstracts; assessing the completeness of reporting of studies of diagnostic accuracy since the STARD initiative and determining if this has had an impact on indexing; determining the impact on diagnostic reviews when using search filters that optimize different searching characteristics (e.g., sensitivity); and evaluating the usefulness of the clinical hedges in the intended users group, clinicians.