Searching meeting abstracts: a comparison between an experienced handsearcher and an indexed, electronic database

Clarke M, Greaves E

Introduction: Meeting abstracts are one way to identify randomised controlled trials (RCTs). Occasionally, these abstracts are included in an indexed bibliographic database. This is so for the annual meeting of the American Society of Clinical Oncology (ASCO) which is in Cancerlit.

Objective: To compare a handsearch of the 1,471 abstracts from the 1992 ASCO meeting with an electronic search of an indexed set of these, as means for identifying RCTs.

Methods: An experienced handsearcher read each of the abstracts and an electronic search of Cancerlit was performed.

Results: The handsearcher found 208 abstracts reporting the results of RCTs, 26 which might be RCTs, and 42 that mentioned current or future RCTs. An electronic search for abstracts tagged with the publication type "randomised controlled trial" identified 179 abstracts. Adding "double blind", "phase III" and the character-string "random" found 119 more. Combining the hand and electronic searching yields 285 abstracts that were, or might be, RCTs. Handsearching found 276 (97%) and the electronic search found 262 (92%) of these. Both found nearly all the probable RCTs, but only 4 of the 26 possible RCTs were found electronically. Some of the latter would be found by adding words such as "placebo" to the search; but others, such as reports mentioning at least two treatments but with an inadequate description of how the groups were formed, probably could not have been found electronically.

Discussion: A combination of hand and electronic searching will yield the highest proportion of RCTs. However, if there are limits on time and resources, it might be preferable to handsearch proceedings which are not available in an indexed database and to do an electronic search alone for those that are. The success of both processes could be improved if abstracts reporting RCTs were more clearly identified.