Table 9.

Comparison of strategies from 1991 with newly developed strategies from 2000, compiled using 2000 data

Year	Approach	Strategy in Ovid format	Sensitivity (%)	Specificity (%)	Precision (%)	Accuracy (%)
1991	Maximise sensitivity	Randomized controlled trial.pt. OR drug therapy.fs. OR therapeutic use.fs. OR random:.tw.	98.3	79.4	13.4	78.6
2000	Maximise sensitivity	Clinical trial.pt. OR random:.mp. OR therapeutic use.fs.	98.9	79.7	13.8	80.3
1991	Maximise specificity	Double.tw. AND blind.tw. OR placebo:.tw.	42.3	98.1	42.2	96.3
2000	Maximise specificity	Randomized controlled trial.mp. OR randomized controlled trial.pt.	93.1	97.4	54.4	97.3

pt=publication type; fs=floating subheading; :=truncation; tw=textword (word or phrase appears in title or abstract); mp=multiple posting (term appears in title, abstract, or MeSH heading).