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.

Sincerely

Mario Petretta

>Department of Translational Medical Sciences

>Naples University Federico II

>Italy

>

Message: 2

Date: Thu, 17 Apr 2014 12:43:06 +0100

From: Michael Dewey <

[hidden email]>

To:

[hidden email],

[hidden email]
Subject: Re: [R] interpreting weight in meta-analysis of proportion

Message-ID: <

[hidden email]>

Content-Type: text/plain; charset="us-ascii"; format=flowed

At 16:30 16/04/2014,

[hidden email] wrote:

>Dear all,

>

>I use R 3.0 for Windows.

>

>I performed a meta-analysis of the prevalence (single proportion)

>reported in 14 different studyes using the command:

>

>res<-metaprop(case,n,sm="PFT", comb.fixed=FALSE, comb.random=TRUE,

>studlab<- paste(Study))

Using which package?

>print(res)

>

>A referee ask a brief explanation of the W-statistic reported in the

>results, in particular, why the summ of the individual weights of all

>the studies is 100%.

What did you expect the weights to sum to, I wonder.

>Any suggestion is welcome.

>

>

>--

>Mario Petretta

>Department of Translational Medical Sciences

>Naples University Federico II

>Italy

>

>

Michael Dewey

[hidden email]
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