Funnel plots for comparing institutional performance
Related Experiment Videos
1MRC Biostatistics Unit, Institute of Public Health, Cambridge CB2 2SR, UK. david.spiegelhalter@mrc-bsu.cam.ac.uk
Abstract:
'Funnel plots' are recommended as a graphical aid for institutional comparisons, in which an estimate of an underlying quantity is plotted against an interpretable measure of its precision. 'Control limits' form a funnel around the target outcome, in a close analogy to standard Shewhart control charts. Examples are given for comparing proportions and changes in rates, assessing association between outcome and volume of cases, and dealing with over-dispersion due to unmeasured risk factors. We conclude that funnel plots are flexible, attractively simple, and avoid spurious ranking of institutions into 'league tables'.
Related Concept Videos
Friedman Two-way Analysis of Variance by Ranks
Significance Testing: Overview
One-Way ANOVA
Wilcoxon Rank-Sum Test
One-Way ANOVA: Equal Sample Sizes
Different sample means can result in different values for the variance estimate: variance between samples. This is because the variance between samples is calculated as the product of the sample size and the variance between the...
Bonferroni Test
The means of different samples are first paired in all possible combinations.
The null hypothesis of the...