Comparison of multiple means with unequal varians

[bjornbc]

Hello
I'm a medical PhD student looking for advice on how to compare means from different studies. All means are based on different sample sizes and have different SD.

The specifics:
I'm looking at a test subjected to patients just before an operation, and one year after an operation. Authors just put the mean preoperative score (plus/minus) the SD and the mean one year score (plus/minus) the SD, and the the p-value.
I'd like to do a comparison of the values across the studies (there are more than 5 studies). I don't have any raw data, apart from the mean and the SD.

Any idea how I do this in STATA?

Obviously I looked around quite a bit, and so far i'm looking at Bonferroni and Holm-Sidak, but are these ok to use? And how do I type the command in STATA without having any data in the data editor?

I really hope you can help me!

Sincerely
Bjørn
Aarhus University Hospital, Denmark

[daniel klein]

There seems to be a focus on either correction for multiple comparisons (e.g. pwcompare) or unequal variances (e.g. ttest ,unequal), but not both at the same time.

You might want to have a look at ttesti, that allows you to enter the means, sds and number of observations and has an option for unequal variances. You can then think about correction of the p-values post-hoc.

Also see pwmc from SSC for an implementation of somewhat old-fashioned approaches to this problem.


Edit:
I just realized you do not have the number of observations? If so, I have no clear idea how to proceed.


Best
Daniel