title: Finding your way out of the forest without a trail of bread crumbs: development and evaluation of two novel displays of forest plots.
abstract: Research has shown that forest plots are a gold standard in the visualization of meta-analytic results. However, research on the general interpretation of forest plots and the role of researchers' meta-analysis experience and field of study is still unavailable. Additionally, the traditional display of effect sizes, confidence intervals, and weights have repeatedly been criticized. The current work presents an online statistical cognition experiment in which a total of 279 researchers with experience in meta-analysis from 36 countries evaluated conventional forest plots and two novel versions of forest plots, namely, thick forest plots and rainforest plots. The results indicate certain biases in the interpretation of forest plots, especially with regard to heterogeneity, the distribution of weights, and the theoretical concept of confidence intervals. Although the two novel displays (thick forest plots and rainforest plots) are associated with slightly longer viewing times, they are at least as well-suited and esthetically and perceptively pleasing as the conventional displays while facilitating the correct and exhaustive interpretation of the meta-analytic information. Furthermore, it is advisable to combine conventional forest plots with distribution information of the individual effects, make confidence lines more visually striking, and to display a background grid in the graph.
authors.affiliation: Department of Basic Psychological Research and Research Methods, School of Psychology, University of Vienna, Vienna, Austria.|Knowledge Media Research Center, Leibniz-Institut für Wissensmedien, Tübingen, Germany.
authors.forename: Anne H E
authors.initials: AH
authors.lastname: Schild
authors.affiliation: Department of Basic Psychological Research and Research Methods, School of Psychology, University of Vienna, Vienna, Austria.|Georg Elias Müller Institut, Georg August Universität of Göttingen, Göttingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Voracek
mesh_terms: D015982:Bias; D003196:Computer Graphics; D016001:Confidence Intervals; D003626:Data Display / Q000706:statistics & numerical data*; D006801:Humans; D015201:Meta-Analysis as Topic; D015233:Models, Statistical
keywords: evaluation; meta‐analysis; rainforest plot; research synthesis; statistical cognition experiment; thick forest plot