Methods for 'vif.rma' Objects

Methods for objects of class "vif.rma".

# S3 method for vif.rma
as.data.frame(x, ...)

Arguments

x

an object of class "vif.rma".

...

other arguments.

References

Viechtbauer, W. (2010). Conducting meta-analyses in R with the metafor package. Journal of Statistical Software, 36(3), 1–48. https://doi.org/10.18637/jss.v036.i03

Examples

### copy data into 'dat'
dat <- dat.bcg

### calculate log risk ratios and corresponding sampling variances
dat <- escalc(measure="RR", ai=tpos, bi=tneg, ci=cpos, di=cneg, data=dat)

### fit mixed-effects meta-regression model
res <- rma(yi, vi, mods = ~ ablat + year + alloc, data=dat)

### get variance inflation factors for all individual coefficients
sav <- vif(res)
sav
#> 
#>  ablat    year  allocrandom  allocsystematic 
#> 1.7697  1.9148       2.0858           2.0193 
#> 

### turn object into a regular data frame
as.data.frame(sav)
#>                 coefs m      vif      sif
#> ablat               2 1 1.769732 1.330313
#> year                3 1 1.914820 1.383770
#> allocrandom         4 1 2.085765 1.444218
#> allocsystematic     5 1 2.019317 1.421027

### get VIFs for ablat and year and the generalized VIF for alloc
sav <- vif(res, btt=list("ablat","alloc","year"))
sav
#> 
#>    spec coefs m    vif    sif 
#> 1 ablat     2 1 1.7697 1.3303 
#> 2 alloc   4:5 2 1.2339 1.0540 
#> 3  year     3 1 1.9148 1.3838 
#> 

### turn object into a regular data frame
as.data.frame(sav)
#>    spec coefs m      vif      sif
#> 1 ablat     2 1 1.769732 1.330313
#> 2 alloc   4:5 2 1.233922 1.053955
#> 3  year     3 1 1.914820 1.383770