Searching the right database. A comparison of four databases for psychiatry journals.

Journal coverage is one factor that affects the retrieval of relevant information from bibliographic databases. The aims of this study were to investigate the coverage of databases for psychiatry journals, and to assess the overlap between databases. Psychiatry journals were identified using Ulrich's International Periodicals Directory and then analysed to see which bibliographic databases indexed the most journals. A total of 213 abstracting and indexing services were listed as indexing at least one of the 977 psychiatry journals identified. The four most frequently cited databases (PSYCLIT, EMBASE, BIOSIS and MEDLINE) indexed 506 (52%) of the psychiatry journals. Of these 506 journals, PSYCLIT indexed 367 (73%), EMBASE 337 (67%), BIOSIS 243 (48%) and MEDLINE 236 (47%). Combining the databases with the highest yields (PSYCLIT and EMBASE) increased the number of journals indexed to 461 (91%). The four databases combined accounted for 90% of all psychiatry journals found to be indexed by at least one abstracting and indexing service. More than 400 journals were not indexed at all. Variations in the overlap between PSYCLIT, EMBASE, BIOSIS and MEDLINE, and the high proportion (35%) of journals indexed in only one of these four databases emphasize the importance of searching more than one or even two databases to ensure optimal coverage of the literature.