Article type
Year
Abstract
Introduction: Graphical displays are used to facilitate the description, exploration, interpretation and communication of the quantitative information contained in systematic reviews. As with any other tool, however, graphics can be misused, leading to inappropriate interpretation of data. It would be ideal to select graphical methods for the display of systematic reviews based on empirical evidence.
Objective: To conduct a systematic search of the literature to identify reports of methods to display graphically the results of systematic reviews.
Methods: A systematic search of MEDLINE (1966 to January 1996), CINHAL (1982 to December 1995), HEALTH (I975 to December 1995), PsychINFO (I967 to February 1996) was conducted and supplemented with a manual search of 9 textbooks on systematic reviews or data display, search of reference lists, and electronic mail contact with the members of the Cochrane Statistical Methods Group and the Epidemio-L Internet discussion list. The archives of the latter were also searched.
Results: Twelve methods were identified: stem-and-leaf displays, funnel plots, the 'confidence interval' method (the one used in most Cochrane Reviews), plots of the difference O-E against variance, the 'odd man out', radial plots of odds ratios, confidence interval function, box plots, 'criteria based meta-analysis' displays, reciprocal scales, the 'sloping line' and 'analysis of proximities' methods. We did not find studies evaluating the usefulness of any of these methods.
Discussion: Despite the widespread use of graphics to represent the results of systematic reviews, we did not identify any empirical evidence to a) support the selection of any particular method, or b) justify the use of graphics to represent the results of systematic reviews. Studies analyzing the effectiveness of these methods on data interpretation and outcomes are required.
Objective: To conduct a systematic search of the literature to identify reports of methods to display graphically the results of systematic reviews.
Methods: A systematic search of MEDLINE (1966 to January 1996), CINHAL (1982 to December 1995), HEALTH (I975 to December 1995), PsychINFO (I967 to February 1996) was conducted and supplemented with a manual search of 9 textbooks on systematic reviews or data display, search of reference lists, and electronic mail contact with the members of the Cochrane Statistical Methods Group and the Epidemio-L Internet discussion list. The archives of the latter were also searched.
Results: Twelve methods were identified: stem-and-leaf displays, funnel plots, the 'confidence interval' method (the one used in most Cochrane Reviews), plots of the difference O-E against variance, the 'odd man out', radial plots of odds ratios, confidence interval function, box plots, 'criteria based meta-analysis' displays, reciprocal scales, the 'sloping line' and 'analysis of proximities' methods. We did not find studies evaluating the usefulness of any of these methods.
Discussion: Despite the widespread use of graphics to represent the results of systematic reviews, we did not identify any empirical evidence to a) support the selection of any particular method, or b) justify the use of graphics to represent the results of systematic reviews. Studies analyzing the effectiveness of these methods on data interpretation and outcomes are required.