Funnel plots: a plot of study effect size versus sample size that helps detect publication bias. If small studies are missing on the negative side, the funnel is asymmetrical.
29 likes 19mo
Topic summary
Follow-up: Individual participant data versus aggregate data
This is a generated summary. It shows the 9 most-liked posts from a topic of 112, in their original order, with the accepted answer included where one exists. It is a reading aid and it will miss nuance — the full topic is the record.
n.norgaard, post #8: Funnel plots: a plot of study effect size versus sample size that helps detect publication bias. If small studies are missing on the negative side, the funnel is asymmetrical. Go to post
Study quality and weighting: some meta-analyses weight all studies equally; others weight by study size or study quality. The choice affects the result and should be stated and justified.
q.zhao_qa, post #20: When trials differ in population, duration and comparator, the pooled estimate answers a question no individual trial asked. That is worth saying before the number is quoted. If this contradicts something upthread, the upthread version may well be the better one. Go to post
On Individual participant data versus aggregate the community has more anecdote than the confidence in this thread implies, and I include my own contribution in that.
m.duarte, post #7: Marking my uncertainty on Individual participant data versus aggregate explicitly. I am confident about the direction, much less confident about the size, and not confident at all that it generalises past the case in the first post. Go to post
Where I part company with post #54, and it is a narrow parting.
Double extraction with disagreement resolution is standard and is worth checking for, because single extraction errors are common and non-random.
r.lundgren, post #22: Posting my Individual participant data versus aggregate numbers with the method attached so they can be discounted properly. Uncontrolled, unblinded, and collected by someone who wanted a particular answer. Go to post
Double extraction with disagreement resolution is standard and is worth checking for, because single extraction errors are common and non-random.
If that is already documented somewhere, ignore me and link it.
Post #81 and I disagree about the size of the effect, not about the direction.
Individual participant data versus aggregate is one of those subjects where the general answer and the answer for a specific case diverge, and the thread will go in circles until someone says which one is being asked for.
30 likes 19mo
a.weiss, post #59: Fixed-effects versus random-effects models: fixed-effects assumes all studies are estimating the same thing and variation is sampling error. Random-effects assumes studies are estimating effects from different distributions and allows between-study variance. Choice matters if heterogeneity is high. Stating my assumptions rather than… Go to post
I read post #107 twice before replying, because I had assumed the opposite.
An observation about Individual participant data versus aggregate that I cannot explain and am posting anyway, on the principle that unexplained observations are more useful public than private.
Read the full topic (112 posts)
This topic was referenced in
- A pooled estimate that changed when one trial was addedEvidence › Meta-analyses · 28 replies
- Reading a meta-analysis you disagree with, fairlyEvidence › Meta-analyses · 13 replies
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