Article type
Year
Abstract
Background: It has long been assumed that information specialists should use high recall search strategies to identify potentially relevant primary studies for systematic reviews. In practice, reviewers, restricted by time and cost, must strive to identify the optimum number of eligible trials, hoping that the studies included in the review will be a representative sample of all eligible trials[1]. Cochrane highly sensitive search strategy (HSSS) is widely used to identify RCTs in Medline. Some literature argue that the precision of the third phase is too low to warrant its use[2,3].
Objectives: To test the performances of four revised HSSSs proposed by Lefebyre and Clarke[3]: combining the top two phases of HSSS with free-text terms volunteer, crossover, versus, and MeSH term CROSS-OVER-STUDIES respectively.
Methods: We identified 96 systematic reviews from Cochrane Database of Systematic Reviews, which used HSSS to find RCTs in Medline. We were able to replicate the subject search for 55 reviews. A known-item search for the included studies of each of the 55 reviews was conducted in order to find their Medline indexing status. Indexed studies were pooled together by review and then combined with the subject search and each of the four proposed search strategies, the top two phases of HSSS, and all three phases of HSSS. These retrievals were used to calculate sensitivity and precision of each of the six search strategies for each review.
Results: The search term versus combined with the top 2 phases of HSSS was able to find two more included studies than the top two phases of HSSS alone, or in combination with any of the other proposed search terms. The overall sensitivity of the four proposed search strategies is very high, ranging from 50% to 100%. In fact, 50% of the reviews achieved a perfect sensitivity (100%). Compared to the precision of all three phases of HSSS (median 0.54%, total retrieval 508,625 studies), the precision of search strategy versus (median 1.48%, total retrieval 171,032 studies) was also improved significantly.
Conclusions: Adding term versus is able to balance the sensitivity and precision to some extent.
References: 1. Jadad AR, Moher D, Klassen TP. Guides for reading and interpreting systematic reviews: II. How did the authors find the studies and assess their quality? Arch Pediatr Adolesc Med. 1998; 152(8):812-817. 2. Boynton J, Glanville J, McDaid D, Lefebvre C. Identifying systematic reviews in MEDLINE: developing an objective approach to search strategy design. J Inf Sci. 1998; 24(3):137-154. 3. Lefebvre C, Clarke MJ. Identifying randomised trials. In: Egger M, Smith GD, Altman DG, editors. Systematic reviews in health care: meta-analysis in context. London: BMJ. 2001: 69-86.
Objectives: To test the performances of four revised HSSSs proposed by Lefebyre and Clarke[3]: combining the top two phases of HSSS with free-text terms volunteer, crossover, versus, and MeSH term CROSS-OVER-STUDIES respectively.
Methods: We identified 96 systematic reviews from Cochrane Database of Systematic Reviews, which used HSSS to find RCTs in Medline. We were able to replicate the subject search for 55 reviews. A known-item search for the included studies of each of the 55 reviews was conducted in order to find their Medline indexing status. Indexed studies were pooled together by review and then combined with the subject search and each of the four proposed search strategies, the top two phases of HSSS, and all three phases of HSSS. These retrievals were used to calculate sensitivity and precision of each of the six search strategies for each review.
Results: The search term versus combined with the top 2 phases of HSSS was able to find two more included studies than the top two phases of HSSS alone, or in combination with any of the other proposed search terms. The overall sensitivity of the four proposed search strategies is very high, ranging from 50% to 100%. In fact, 50% of the reviews achieved a perfect sensitivity (100%). Compared to the precision of all three phases of HSSS (median 0.54%, total retrieval 508,625 studies), the precision of search strategy versus (median 1.48%, total retrieval 171,032 studies) was also improved significantly.
Conclusions: Adding term versus is able to balance the sensitivity and precision to some extent.
References: 1. Jadad AR, Moher D, Klassen TP. Guides for reading and interpreting systematic reviews: II. How did the authors find the studies and assess their quality? Arch Pediatr Adolesc Med. 1998; 152(8):812-817. 2. Boynton J, Glanville J, McDaid D, Lefebvre C. Identifying systematic reviews in MEDLINE: developing an objective approach to search strategy design. J Inf Sci. 1998; 24(3):137-154. 3. Lefebvre C, Clarke MJ. Identifying randomised trials. In: Egger M, Smith GD, Altman DG, editors. Systematic reviews in health care: meta-analysis in context. London: BMJ. 2001: 69-86.