# How to create common effect size estimate for meta-analysis based on a mix of mean changes and raw group means and standard deviations?

I am trying to do a meta analysis, involving continuous data. I am trying to do this meta analysis in Stata using the metan command.

However, this data is organized in different fashions, where I have some studies with data listed as change in means with their standard errors and other data which is listed as the raw means and standard deviations.

Is there a way to combine this data and proceed with the analyses?

• To begin with, I suggest reading: Morris, S. B., & DeShon, R. P. (2002). Combining effect size estimates in meta-analysis with repeated measures and independent-groups designs. Psychological Methods, 7, 105-125. – Wolfgang Sep 15 '11 at 13:32

I'm assuming that you want to compute standardised group mean differences for all studies (i.e., Cohen's $d$).