R: Funnel plot for publication bias

funnelplot {rmeta} | R Documentation

## Funnel plot for publication bias

### Description

Plots the treatment difference for trials against the size of the trial (or other specified variable). Asymmetry in the plot often indicates publication bias. Generic, with methods for meta-analysis objects.

### Usage

    funnelplot(x,...)
    ## Default S3 method:
    funnelplot(x, se, size=1/se, summ=NULL,
            xlab="Effect", ylab="Size", colors=meta.colors(),
            conf.level=0.95, plot.conf=FALSE,
            zero=NULL, mirror=FALSE, ...)

### Arguments

`x` | Treatment difference
`se` | Standard error of `x`
`size` | Variable for the vertical axis
`summ` | summary treatment difference
`xlab` | x-axis label
`ylab` | y-axis label
`colors` | list of colors for components of the plot
`conf.level` | For confidence interval plotting
`plot.conf` | Plot confidence intervals instead of just points?
`zero` | location of a null hypothesis line
`mirror` | Add points reflected around `summ`?
`...` | further arguments to be passed from or to methods.

### Details

With the default value of `size` the plot should appear as a upwards-pointing funnel shape. Publication bias often causes one side of the funnel to be trimmed near the base. The `mirror` plot creates a symmetric funnel by reflecting the plot around the `summ` value. In the presence of publication bias the added points will separate from the real studies.

### Value

Used for its side-effect.

### Author(s)

Thomas Lumley

### See Also

`meta.DSL`, `meta.MH`, `meta.summaries`, `metaplot`

### Examples

    data(catheter)
    a <- meta.MH(n.trt, n.ctrl, col.trt, col.ctrl, data=catheter,
                 names=Name, subset=c(13,6,5,3,7,12,4,11,1,8,10,2))
    funnelplot(a$logOR, a$selogOR)
    funnelplot(a$logOR, a$selogOR,
               plot.conf=TRUE, summ=a$logMH, mirror=TRUE)
    funnelplot(a, plot.conf=TRUE)

[Package rmeta version 2.16 Index]