metabias {metansue}

Test for Funnel Plot Asymmetry for “meta.nsue” Objects

Description

Test for funnel plot asymmetry.

Usage

metabias(x, ...)

## S3 method for class 'meta.nsue'
metabias(x, maxiter = 100, tol = 1e-06, ...)

Arguments

x

an object of class "meta.nsue".

maxiter

maximum number of iterations in the REML estimation of \tau^2.

tol

tolerance in the REML estimation of \tau^2.

...

other arguments (currently ignored).

Details

The test, based on a meta-regression by the standard error, aims to detect asymmetry in the funnel plot, which may be an indication of publication bias.

However, results should be taken with caution, especially if there are too few studies (at least 10 studies were suggested by Sterne et al. (2011)), if sample sizes are too similar, if there are outliers or influential studies or subgroups in the plot, or if dichotomous outcomes have been used (some effect estimates are naturally correlated with their standard errors).

Also, publication bias cannot be excluded in case of negative results, whereas it is only one of the possible explanations in case of positive results - others being selective outcome reporting, poor methodological quality in the smaller studies, true heterogeneity (i.e. effect size truly depends on study size), and etcetera (Egger 1997).

Value

A list with class "htest" containing the following components:

data.name

a character string giving the name of the data.

method

a character string indicating that a "meta.nsue" regression test for funnel plot asymmetry was performed.

statistic

the value of the z-statistic.

p.value

the p-value for the test.

Author(s)

Joaquim Radua

References

Egger, M., Smith, G.D., Schneider, M., Minder, C. (1997) Bias in meta-analysis detected by a simple, graphical test. BMJ, 315, 629–634, doi:10.1136/bmj.315.7109.629.

Radua, J., Schmidt, A., Borgwardt, S., Heinz, A., Schlagenhauf, F., McGuire, P., Fusar-Poli, P. (2015) Ventral striatal activation during reward processing in psychosis. A neurofunctional meta-analysis. JAMA Psychiatry, 72, 1243–51, doi:10.1001/jamapsychiatry.2015.2196.

Albajes-Eizagirre, A., Solanes, A, Radua, J. (2019) Meta-analysis of non-statistically significant unreported effects. Statistical Methods in Medical Research, 28, 3741–54, doi:10.1177/0962280218811349.

Sterne, J.A., Sutton, A.J., Ioannidis, J.P., Terrin, N., Jones, D.R., Lau, J., Carpenter, J., Rucker, G., Harbord, R.M., Schmid, C.H., Tetzlaff, J., Deeks, J.J., Peters, J., Macaskill, P., Schwarzer, G., Duval, S., Altman, D.G., Moher, D., Higgins, J.P. (2011) Recommendations for examining and interpreting funnel plot asymmetry in meta-analyses of randomised controlled trials. BMJ, 343, d4002, doi:10.1136/bmj.d4002.

See Also

funnel for plotting funnel plots.

meta for conducting a meta-analysis.

Examples

t <- c(3.4, NA, NA, NA, NA, 2.8, 2.1, 3.1, 2.0, 3.4)
n <- c(40, 20, 22, 24, 18, 30, 25, 30, 16, 22)
m <- meta(smc_from_t(t, n))
metabias(m)