Meta-analysis

Hi All!
If you have been directed to this post, you stated that you were interested in, or are currently using, quantitative meta-analytic techniques in your analyses. Please use this forum to connect with each other either in person or online... It would be great if we could share knowledge and advice with each other!

mbowdring wrote:I'm not sure if it makes sense due to there being a limited number of studies (about 12) and the studies being split between experimental and observational designs.

An ideal number for comps (in my opinion) would be around 20-40 studies, especially if you hope to publish it afterwards. I passed my comps with a meta-analysis of 11 studies, so it is possible, but I don't think I'd have much luck trying to publish it in that form. My plan is to loosen the inclusion criteria in order to expand it to ~25 studies and then try again after dissertation. Knowing what I know now, I would still pick this project and would still do a meta-analysis, but I would probably loosen the inclusion criteria from the start. If this is the topic you are set on and there are no ways to loosen the criteria to get more studies, I think it's still worth it to do a meta-analysis. It can be difficult and stressful to learn, but you'd have help from CAMEL and it really makes the write-up easier and your conclusions a lot more precise.

mbowdring wrote:Furthermore, about half of the studies have a positive effect of alcohol, about a quarter have a negative effect, and about a quarter have no (significant) effect. So although there will likely not be a large (or potentially even significant) effect if I use meta-analysis, could it still make sense to do it?

This is a great reason to do a meta-analysis! The overall effect size might not be significant, but if there is a lot of heterogeneity among the studies contributing to it, you would have the potential to do some really interesting and (hopefully) fruitful moderation analyses. The dream would be to identify the variables that explain why some studies have found negative results and others have found positive ones. You probably wouldn't have enough power to answer this question definitively, but you could reveal some important information that might motivate future work in the area (e.g., your dissertation).

Thanks Jeff, this is really helpful!! I'm sure I'll have more questions as I move forward, but now I feel a bit more confident working toward proposing a meta-analysis.