# Question arising from JAMA Guide article "Odds Ratios—Current Best Practice and Use"

**URL:** <https://discourse.datamethods.org/t/question-arising-from-jama-guide-article-odds-ratios-current-best-practice-and-use/483>\
**Category:** journal club\
**Tags:** interpretation\
**Created:** [August 21, 2018, 3:16am UTC](https://discourse.datamethods.org/t/question-arising-from-jama-guide-article-odds-ratios-current-best-practice-and-use/483 "2018-08-21T03:16:10Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![timdisher](https://discourse.datamethods.org/letter_avatar_proxy/v4/letter/t/3d9bf3/32.png) [@timdisher](https://discourse.datamethods.org/u/timdisher)\
**Post date:** [August 21, 2018, 11:42pm UTC](https://discourse.datamethods.org/t/question-arising-from-jama-guide-article-odds-ratios-current-best-practice-and-use/483/7 "2018-08-21T23:42:32Z")

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> [@f2harrell](#):
>
> If you were to think that unadjusted odds ratios were comparable across studies, this is not the case. That’s because these unadjusted ORs are functions of the (hidden to the analysis) subject characteristics.

Totally agree that unadjusted are no better (and almost certainly worse). My impression from these data are that efforts to synthesize data from observational and randomized trials is even harder than the current literature base makes it out to be. Not sure about the fields you work in most commonly, but everyone in my end of neonatology seems to have their own pet characteristics to adjust for. Could this be addressed at all by working from an assumed baseline risk and then converting ORs to RRs or absolute risk?

> [@f2harrell](#):
>
> It is true that for hazard ratios, odds ratios, etc. you can’t compare effect ratios across different sets of adjustors. The odds ratios have a fundamentally different meaning when adjustors change.

Seeing you say this so matter-of-factly juxtaposed against the all to common narrative of univariate adjustments followed by adding predictors to show how odds ratios change in response to “adjustment” is a weird combination of funny and frustrating. I wonder if you would mind expanding on the last sentence, is this a marginal vs conditional type scenario?

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