MAd (version 0.8-3)

mareg: Meta-Regression

Description

Meta-regression function for a single or multiple predictor model. This function is a wrapper for the rma() function in the metafor package (Viechtbauer, W, 2010). Please see http://CRAN.R-project.org/package=metafor for details or for more advanced functionality with the rma() function.

Usage

mareg(formula, var, data, method = "REML", subset,  digits = 3, ...)

Value

estimate

Meta-regression coefficient estimate.

se

Standard error of the estimate coefficient.

z

z-value.

ci.l

Lower 95% confidence interval.

ci.u

Upper 95% confidence interval.

p

p-value (significance level).

QE

Q-error. Measure of error in the model.

QE.df

Degrees of freedom for Q-error.

QEp

Q-error p-value (for homogeneity).

QM

Q-model. Measure of model fit.

QM.df

Degrees of freedom for Q-model.

QMp

Q-between p-value (for homogeneity). QM and QMp provide the test of whether the moderator variable(s) account for significant variance among effect sizes.

Arguments

formula

This is a formula based function, similar to other functions in R (e.g., lm), where the criterion variable (e.g., Hedges g in this case) is dependent on ('~') the predictor variables (e.g., moderators). The formula for two moderators would take this form: mareg(g ~ mod1 + mod2, var.g, data), where g is the criterion variable predicted by mod1 and mod2. The variance (var) of each g is var.g in this case.

var

Variance of g.

data

Aggregated data.frame (see agg function for setting up the dataset for these analyses) with id, g (unbiased standardized mean difference), var.g (variance of g) for each study.

method

Default is REML (Restricted-Maximal Likelihood), which is the standard random effects method. For fixed effects, use FE. Other options are specified in the metafor package manual ('rma' function).

subset

an optional vector specifying a subset of observations to be used in the fitting process.

digits

Number of digits to output. Default is 3.

...

Additional arguments to be passed to rma().

Details

See Wolfgang Viechtbauer (2010). metafor: Meta-Analysis Package for R. R package version 1.1-0. for the details of the rma() function. http://CRAN.R-project.org/package=metafor

References

Wolfgang Viechtbauer (2010). metafor: Meta-Analysis Package for R. R package version 1.1-0. http://CRAN.R-project.org/package=metafor

See Also

plotcon

Examples

# install metafor
# install.packages('metafor', dependencies = TRUE)

# Sample data
data(dat.sim.final)


# Examples

# OMNIBUS
m0 <- mareg(es~1, var=var, data=dat.sim.final)
summary(m0)

# META-REGRESSION
m1 <- mareg(es~dose, var=var, data=dat.sim.final)
summary(m1)  # SINGLE MODERATOR

m2 <- mareg(es~stress, var=var, data=dat.sim.final)
summary(m2)  # SINGLE MODERATOR

m3 <- mareg(es~dose + stress, var=var, data=dat.sim.final)
summary(m3)  # MULTIPLE MODERATOR