Abstract:
Objective To introduce how to draw a contour-enhanced funnel in R software and its application in meta-analysis.
Methods It was illustrated on an example data to draw a contour-enhanced funnel by using funnel() function and trimfill() function in meta package in R software, and to perceive the missing studies in areas of statistical significance from the plot.
Results The contour-enhanced funnel was asymmetry, and the studies seem to be missing in areas of non-significance, and it was explained that funnel plot asymmetry may be due to publication bias.
Conclusions Contour-enhanced funnel could be used to help distinguish publication bias from other cause of funnel plot asymmetry.