tag:blogger.com,1999:blog-4266300416434206693.post8900761204814566818..comments2023-08-11T12:04:42.077+02:00Comments on The Church of Rationality: Two Problems with Using Meta-Analysis on Observational DataLemmusLemmushttp://www.blogger.com/profile/00917054221547240969noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-4266300416434206693.post-80029063041785753642008-08-02T15:17:00.000+02:002008-08-02T15:17:00.000+02:00Concerning income, I could see a study that looks ...Concerning income, I could see a study that looks at both individual/family income and neighbourhood poverty using a multilevel model. In fact, that sounds rather interesting. But in medical contexts I'd probably always wonder what that proxied. Can't afford medication? Too many fast-food places nearby? In fact, I'm probably going to post something about that, once I get round to reading <I>that</I> paper, so <I>stay tuned</I>.<BR/><BR/>As for the paper you read, it seems the authors presented the results well enough so you could spot the problem. Hats off - that's what I meant by being careful.<BR/><BR/>I once had the wild idea that one could weigh the results of meta-analyses (which I have no special expertise in) by the R-squared of the regressions. But I haven't really thought that through and the point about overcontrol you mention seems to speak against that.LemmusLemmushttps://www.blogger.com/profile/00917054221547240969noreply@blogger.comtag:blogger.com,1999:blog-4266300416434206693.post-54762110742966471962008-08-02T13:42:00.000+02:002008-08-02T13:42:00.000+02:00I was looking at a meta-analysis of this type fair...I was looking at a meta-analysis of this type fairly recently and it nicely illustrated your point (1). All the positive studies had a tiny number of confounding variables corrected for (age, gender, that's about it) while the negative studies all corrected for known causal factors that could mediate the association. A few studies even had over-correction where they were controlling for variables that seemed to be alternative proxies for the same thing the study was looking at (like controlling for family income when looking for an association between something and poor or rich areas and concluding there is no reationshop with poverty), so no wonder the studies were negative.pjhttps://www.blogger.com/profile/06832177812057826894noreply@blogger.com