At 18:39 04/04/2012, mp.sylves...@gmail.com wrote:
Greetings,
I wish to conduct a meta-analysis for which the outcome is a continuous
variable measured on the same individuals before and after an intervention.
Hence, the comparison is not made between two groups, but within groups, at
diffrent times.
Each study reports the mean outcome and SD before the intervention and the
mean outcome and SD after the intervention. While p-values for paired
t-test (or similar methods for paired data) are reported in the studies, no
estimate of the variability of the individual differences are available.
If you know the p-value you can generate the t-value
If you know the t-value and the mean difference you can back
calculate the standard errors of the differences.
Having said that I am not absolutely sure what the design of the
primary studies you are analysing is so my answer may not apply
directly to your problem.
Can metafor deal with this sort of meta-analysis? I know that I can
technically run metafor on these data, assuming that the groups are
independent but my inference is likely to be wrong. On the other hand, I
have no idea of the correlation within individuals.
Thanks in advance,
MP
[[alternative HTML version deleted]]
Michael Dewey
i...@aghmed.fsnet.co.uk
http://www.aghmed.fsnet.co.uk/home.html
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