[force_reboot]

On what basis do you say that meta-analysis is not credible? From my stats background, (but without any direct experience in meta-analysis) I would say that they could be problematic because the N is very small and so have a lot less to work with, and more temptation to use fancy statistical techniques with hidden assumptions. On the other hand, what do you do when you have 50 studies of varying quality, no one of which is has such a compelling methodology as to eclipse the others? In that case it seems like meta-analysis is the least bad option.

[slr555]

Your point is a good one but in medicine the issue tends to be that a lot of studies with varying controls and endpoints are being lumped together and presented as a coherent whole. In reality the distortions (and in some cases biases of the researcher) that are introduced leave the data often untenable. You are absolutely right that powering medical studies correctly is a critical issue. It is also critical that when making pronouncements about important treatment modalities that the research be of the highest quality.

Meta-analyses are often used in so creating so called evidence based medicine standards which are sometimes cost cutting efforts dressed up like research.

As a trauma surgeon recently said to me recently, "They said they designed it using evidence based medicine. They didn't say whose evidence".