Funnel Plot (metafor)

Authors

[Editor] Hu Zheng;

[Contributors]

Can be used to show potential bias factors in Meta-analysis.

Setup

System Requirements: Cross-platform (Linux/MacOS/Windows)
Programming language: R
Dependent packages: metafor; ggplotify

# Install packages
if (!requireNamespace("metafor", quietly = TRUE)) {
  install.packages("metafor")
}
if (!requireNamespace("ggplotify", quietly = TRUE)) {
  install.packages("ggplotify")
}

# Load packages
library(metafor)
library(ggplotify)

Data Preparation

# Load data
data <- read.delim("files/Hiplot/057-funnel-plot-metafor-data.txt", header = T)

# Convert data structure
data2 <- escalc(ri=ri, ni=ni, data = data, measure="ZCOR")
res <- rma(yi, vi, data = data2)

# View data
head(data2)


              authors year  ni    ri controls          design   a_measure 
1     Axelsson et al. 2009 109 0.187     none cross-sectional self-report 
2     Axelsson et al. 2011 749 0.162     none cross-sectional self-report 
3        Bruce et al. 2010  55 0.340     none     prospective       other 
4  Christensen et al. 1999 107 0.320     none cross-sectional self-report 
5 Christensen & Smith 1995  72 0.270     none     prospective       other 
6        Cohen et al. 2004  65 0.000     none     prospective       other 
  c_measure meanage quality     yi     vi 
1     other   22.00       1 0.1892 0.0094 
2       NEO   53.59       1 0.1634 0.0013 
3       NEO   43.36       2 0.3541 0.0192 
4     other   41.70       1 0.3316 0.0096 
5       NEO   46.39       2 0.2769 0.0145 
6       NEO   41.20       2 0.0000 0.0161

Visualization

# Funnel Plot
p <- as.ggplot(function(){
  funnel(x = res, main = "Funnel Plot (metafor)",
         level = c(90, 95, 99), shade = c("white","#a90e07","#d23e0b"), refline = 0)
  })

p