[R] interpreting weight in meta-analysis of proportion

[Bernd Weiss]

On 18.04.2014 13:02, petretta at unina.it wrote:
> Prof. Dewey, sorry for the trivial question and many thank for the replay.
> 
> 
>> Using which package?
> 
> In this case I used the meta package, but I know that for all but the
> DerSimonian-Laird method the R function rma.uni of R package metafor is
> called internally.
> 
>> What did you expect the weights to sum to, I wonder.
> 
> I think that, to better explain the influence of single study in pooling
> the effect size, the weight are presented as percentage of the sum of
> total weight of each study, but I ask for a confirm. Nevertheless, I ask
> if it is possible to obtain for each study the value of the absolute
> weight, other than the relative weight, or at least the absolute value of
> the sum of the weights.
> 

## This is an example from the examples-section
res <- metaprop(4:1, c(10, 20, 30, 40), comb.fixed=FALSE, comb.random=TRUE)

## Object res contains a lot of interesting information
## Open ?metaprop and read the section on "values"
str(res)

## Obtaining the random-effects weights
res$w.random

## Calculating relative weights manually
res$w.random/(sum(res$w.random))

HTH,

Bernd