Graphical Presentation of Results
Visualizations of data are one of the most compelling means to effectively communicate ideas in science. Graphs present data in a visual form enabling the reader to read values, identify patterns, assess the outcome of a statistical technique, or analyze relationships within or between variables. Effective visualizations of meta-analyses have been discussed extensively in the evidence-based medical literature and to a lesser extent in ecology and evolutionary biology. The two most common meta-analysis plots are derived from the social sciences and include (1) modified error bar plots called forest plots used to summarize and compare weighted mean effects, and (2) meta-regression plots (scatterplots with significant fit lines) used to show the relationship between main effects and covariates. This chapter describes these two standard meta-analysis plots and provides sample graphics to illustrate usage. Details are also included for the use of simple histograms and funnel plots.