Here's a question #epitwitter:
If an n=80 study randomizes into two groups, stratified by age AND gender, is it still randomized?
Ah ok then. I see what you mean it isn't really an issue it just makes the stratification a bit pointless I guess
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Exactly. Stratification is sometimes done for pragmatic reasons - eg site so each hospital has their own randomisation envelopes.
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When stratifying for non-admin reasons you need also adjust for the stratification in the analysis. The objective is to increase power by adj, and additionally by stratif to avoid colinearity of the adj vars and treatment. But with few pats/stratum they again become colinear.
End of conversation
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