title: Meta-analysis: an update.
abstract: A fairly new type of research, termed meta-analysis, attempts to analyze and combine the results of previous reports. In 1992 we updated our 1987 survey of 86 meta-analyses of randomized control trial reports in the english language literature with an additional 78. We evaluated the quality of these meta-analyses using a scoring method that lists 23 items in six major areas: study design, combinability, control of bias, statistical analysis, sensitivity analysis, and application of results. Of the 23 individual items, the mean number satisfactorily addressed was 7.63 +/- 2.84 (mean +/- S.D.) for 40 papers published from 1955 through 1982, 6.80 +/- 3.86 for 66 papers published from 1983 through 1986, and 11.91 +/- 4.79 for 58 papers published from 1987 through 1990 (F = 31.3, p < .001). We noted that methodology has definitely improved since our first survey of meta-analyses, but an urgent need still exists for a better search of the literature, quality evaluation of trials, and a synthesis of the results. Recently, meta-analysis has expanded to cover non-randomized studies, including evaluation of diagnostic tests and pooling of epidemiologic studies. There is growing concern for standards, and several methodologic issues remain unresolved.
authors.affiliation: Thomas C. Chalmers Clinical Trials Unit, Mount Sinai School of Medicine of CUNY, New York, USA.
authors.forename: H S
authors.initials: HS
authors.lastname: Sacks
authors.forename: D
authors.initials: D
authors.lastname: Reitman
authors.forename: D
authors.initials: D
authors.lastname: Pagano
authors.forename: B
authors.initials: B
authors.lastname: Kupelnick
mesh_terms: D015982:Bias; D003625:Data Collection / Q000379:methods; D003627:Data Interpretation, Statistical; D015201:Meta-Analysis as Topic; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D012107:Research Design