Topic summary
Confounding by indication, explained with a concrete example
This is a generated summary. It shows the 5 most-liked posts from a topic of 26, 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.
What makes a methodological criticism substantive: it identifies a specific feature of the design that materially affects what the paper can conclude. "Small sample size" alone is weak. "Small sample size for a rare outcome, so the confidence interval is wide" is stronger.
32 likes 11mo
to.varga, post #1: On the subject in the title: Confounding by indication, explained with a concrete example Working notes rather than a conclusion. Comparing SURMOUNT-1 ( N Engl J Med , 2022) with SURPASS-2 ( N Engl J Med , 2021) and finding the comparison harder than it looks. Different populations, different durations, different endpoints defined… Go to post
Bias towards the null and bias away from the null: different criticisms have different directions. Differential dropout might bias away from null; conservative statistical analysis might bias toward null.
For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.
12 likes 11mo
b.demir, post #3: post #2 answers the question as asked. The question underneath it is different. Publication bias: a single published positive trial is weaker evidence than multiple published trials with consistent results. Asking whether there are unpublished negative trials is a fair critical question. Go to post
Multiple comparisons: if a paper reports many outcomes, the chance of a spurious association by random chance is real. Pre-specification of primary outcomes matters and secondary analyses are weaker evidence.
Read the full topic (26 posts)
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