altmeta (version 3.3)

metapb: Detecting and Quantifying Publication Bias/Small-Study Effects

Description

Performs the regression test and calculates skewness for detecting and quantifying publication bias/small-study effects.

Usage

metapb(y, s2, model)

Arguments

y

a numeric vector specifying the observed effect sizes in the collected studies; they are assumed to be normally distributed.

s2

a numeric vector specifying the within-study variances.

model

a characher string specifying the fixed-effect ("FE") or random-effects ("RE") model. If not specified, this function uses the \(Q\) statistic to test for heterogeneity: if the p-value is smaller than 0.05, model is set to "RE"; otherwise, model = "FE".

Value

This function returns a list containing measures of publication bias, their 95% confidence intervals, and p-values. Specifically, the components include:

n

the number of studies in the meta-analysis.

p.Q

the p-value of the \(Q\)-test for heterogeneity.

I2

the \(I^2\) statistic for quantifying heterogeneity.

tau2

the DerSimonian--Laird estimate of the between-study variance.

model

the model setting ("FE" or "RE").

std.dev

the standardized deviates of the studies.

reg.int

the estimate of the regression intercept for quantifying publication bias.

reg.int.ci

the 95% CI of the regression intercept.

reg.pval

the p-value of the regression intercept.

skewness

the estimate of the skewness for quantifying publication bias.

skewness.ci

the 95% CI of the skewness.

skewness.pval

the p-value of the skewness.

combined.pval

the p-value of the combined test that incorporates the regression intercept and the skewness.

Details

This function derives the measures of publication bias introduced in Lin and Chu (2018).

References

Egger M, Davey Smith G, Schneider M, Minder C (1997). "Bias in meta-analysis detected by a simple, graphical test." BMJ, 315(7109), 629--634. <10.1136/bmj.315.7109.629>

Lin L, Chu H (2018). "Quantifying publication bias in meta-analysis." Biometrics, 74(3), 785--794. <10.1111/biom.12817>

Examples

# NOT RUN {
data("dat.slf")
attach(dat.slf)
metapb(y, s2)
detach(dat.slf)

data("dat.ha")
attach(dat.ha)
metapb(y, s2)
detach(dat.ha)

data("dat.lcj")
attach(dat.lcj)
metapb(y, s2)
detach(dat.lcj)
# }