title: Weighing Evidence "Steampunk" Style via the Meta-Analyser.
abstract: The funnel plot is a graphical visualization of summary data estimates from a meta-analysis, and is a useful tool for detecting departures from the standard modeling assumptions. Although perhaps not widely appreciated, a simple extension of the funnel plot can help to facilitate an intuitive interpretation of the mathematics underlying a meta-analysis at a more fundamental level, by equating it to determining the center of mass of a physical system. We used this analogy to explain the concepts of weighing evidence and of biased evidence to a young audience at the Cambridge Science Festival, without recourse to precise definitions or statistical formulas and with a little help from Sherlock Holmes! Following on from the science fair, we have developed an interactive web-application (named the Meta-Analyser) to bring these ideas to a wider audience. We envisage that our application will be a useful tool for researchers when interpreting their data. First, to facilitate a simple understanding of fixed and random effects modeling approaches; second, to assess the importance of outliers; and third, to show the impact of adjusting for small study bias. This final aim is realized by introducing a novel graphical interpretation of the well-known method of Egger regression.
authors.affiliation: MRC Integrative Epidemiology Unit, University of Bristol , Bristol , UK.
authors.forename: Jack
authors.initials: J
authors.lastname: Bowden
authors.affiliation: MRC Biostatistics Unit, University of Cambridge , Cambridge , UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Jackson
keywords: Bias adjustment; Egger regression; Funnel plot; Meta-analysis