On 7/24/2009 11:40 AM, Frank Pearson wrote:> I had found the author's (Wolfgang Viechtbauer) earlier meta-analytic
code in R, MiMa, useful. so I have been exploring metafor using an example
dataset from MiMa. metafor provides a lot more. However, MiMa provided
parameter estimates, standard errors, z values, etc. for individual moderators
in the meta-analysis, but I don't see how to obtain these from metafor.
Have you any help about how to get this?
>
> Frank
Hi Frank:
Which function in the metafor package are you using to fit the
meta-regression model? The following works for me to reproduce one of
the analyses in the MiMa Tutorial
(http://www.wvbauer.com/downloads/mima_tutorial.pdf):
library(metafor)
f <- "STUDY N1 N2 YI VI MINUTES TRAINED MEANAGE
1 30 30 0.444 0.068 30 0 28
2 46 39 -0.495 0.049 10 0 42
3 15 15 0.195 0.134 20 1 31
4 10 10 0.546 0.207 40 1 39
5 12 12 0.840 0.181 20 1 17
6 10 10 0.105 0.200 30 1 51
7 26 24 0.472 0.082 15 1 26
8 18 14 -0.205 0.128 10 0 64
9 12 12 1.284 0.201 45 1 48
10 12 12 0.068 0.167 30 1 40
11 15 15 0.234 0.134 30 1 52
12 12 12 0.811 0.180 30 1 33
13 15 15 0.204 0.134 30 1 20
14 18 18 1.271 0.134 60 1 27
15 15 15 1.090 0.153 45 1 52
16 43 35 -0.059 0.052 10 1 61"
madf <- read.table(textConnection(f), sep=" ", header=TRUE)
rma(YI, VI, mods=cbind(MINUTES, TRAINED, MEANAGE), data=madf)
Mixed-Effects Model (k = 16; tau^2 estimator: REML)
tau^2 (estimate of residual amount of heterogeneity): 0 (SE = 0.0472)
tau (sqrt of the estimate of residual heterogeneity): 0
Test for Residual Heterogeneity:
QE(df = 12) = 9.1238, p-val = 0.6923
Test of Moderators (coefficient(s) 2,3,4):
QM(df = 3) = 28.8348, p-val = 0
Model Results:
estimate se zval pval ci.lb ci.ub
intrcpt -0.2956 0.3488 -0.8473 0.3968 -0.9792 0.3881
MINUTES 0.0250 0.0067 3.7149 0.0002 0.0118 0.0381 ***
TRAINED 0.3011 0.1953 1.5415 0.1232 -0.0817 0.6839
MEANAGE -0.0060 0.0063 -0.9518 0.3412 -0.0182 0.0063
---
Signif. codes: 0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1
> sessionInfo()
R version 2.9.1 (2009-06-26)
i386-pc-mingw32
locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] metafor_0.5-0
hope this helps,
Chuck
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--
Chuck Cleland, Ph.D.
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