RE: st: Meta analysis in single group,

["Tiago V. Pereira" <tiago.pereira@mbe.bio.br>]

Dear Asad,

I solved that problem writing my own code (both fixed-effects 'inverse
variance' and DerSimonian-Laird methods). They are easy to implement, and
I think that in your case this is the only way out.

-metan- has an option to perform analyses using the effect and its
standard error. However, that approach will not be suitable when data is
continuous, since the normal approximation may not be valid depending on
the sample size.

To address your question, you need  to estimate the mean difference (pos
vs pre) for each study. Then, an appropriate variance estimate should be
computed. To do that, a proper correlation estimate has to be known (or
estimated from the data).

Once you have the mean effect and its variance, a variance-weighted
analysis can be performed.

Let me know if you need help.

Tiago


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