# \#random-effects

**URL:** https://discourse.datamethods.org/tag/random-effects/110.md

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## [Random effects analysis in clinical trials](https://discourse.datamethods.org/t/random-effects-analysis-in-clinical-trials/28517)

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**Author:** [@alvespedros](https://discourse.datamethods.org/u/alvespedros)\
**Replies:** 2\
**Last updated:** [November 4, 2025, 11:36am UTC](https://discourse.datamethods.org/t/random-effects-analysis-in-clinical-trials/28517 "2025-11-04T11:36:54Z")

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Hello, I’m working on a SAP for a clinical trial with three levels of clustering: physicians, hospitals, and cities. My outcome is binary, and I’m particularly interested in the conditional interpretation of the odds ra…

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## [Comparisons of Physicians and LLMs with Technical Replicates](https://discourse.datamethods.org/t/comparisons-of-physicians-and-llms-with-technical-replicates/15508)

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**Author:** [@rjg](https://discourse.datamethods.org/u/rjg)\
**Replies:** 1\
**Last updated:** [June 6, 2024, 7:51pm UTC](https://discourse.datamethods.org/t/comparisons-of-physicians-and-llms-with-technical-replicates/15508 "2024-06-06T19:51:32Z")

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Summary of Question: How to compare performance of a large language model (LLM) and physicians on some medical task, using multiple technical replicates from the LLM? I’ve noticed several studies comparing LLMs and phys…

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## [Random vs. fixed effects meta-analysis](https://discourse.datamethods.org/t/random-vs-fixed-effects-meta-analysis/7361)

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**Author:** [@f2harrell](https://discourse.datamethods.org/u/f2harrell)\
**Replies:** 22\
**Last updated:** [January 20, 2024, 4:12pm UTC](https://discourse.datamethods.org/t/random-vs-fixed-effects-meta-analysis/7361 "2024-01-20T16:12:38Z")

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I’m seeking clarity on when to use random effects vs. fixed effects for studies in a meta-analysis. Here’s what I’ve come to believe: Fixed effects account for and absorb variability just like random effects Fixed eff…

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## [Mixed models modelling](https://discourse.datamethods.org/t/mixed-models-modelling/7061)

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**Author:** [@sebastian](https://discourse.datamethods.org/u/sebastian)\
**Replies:** 14\
**Last updated:** [October 26, 2023, 8:27pm UTC](https://discourse.datamethods.org/t/mixed-models-modelling/7061 "2023-10-26T20:27:48Z")

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Imagine an RCT, one intervention and one control group, with 5 timepoints, ~270 individuals for whom data are available. I fit a mixed model in R looking like this: Outcome ~ time + group + time:group + baseline\_outcome…

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## [Random effect model for multi center prognostic markers](https://discourse.datamethods.org/t/random-effect-model-for-multi-center-prognostic-markers/6821)

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**Author:** [@trumanfrancis](https://discourse.datamethods.org/u/trumanfrancis)\
**Replies:** 5\
**Last updated:** [May 30, 2023, 2:00am UTC](https://discourse.datamethods.org/t/random-effect-model-for-multi-center-prognostic-markers/6821 "2023-05-30T02:00:50Z")

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In the Gerds and Kattan Medical Risk Prediction text they mention that " Including the cohort variable as a random effect in a logistic or Cox regression model would make it possible to predict new patients from other ce…

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## [Time-varying covariates in a shared frailty survival model](https://discourse.datamethods.org/t/time-varying-covariates-in-a-shared-frailty-survival-model/3792)

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**Author:** [@caseyleemcatee](https://discourse.datamethods.org/u/caseyleemcatee)\
**Replies:** 0\
**Last updated:** [September 28, 2020, 3:47pm UTC](https://discourse.datamethods.org/t/time-varying-covariates-in-a-shared-frailty-survival-model/3792 "2020-09-28T15:47:35Z")

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Good morning, I am somewhat new to survival analysis. I am having trouble coding a survival analysis model for recurrent events that includes time-varying covariates. Due to the data structure, a shared frailty survival…

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## [Risk-adjusting centers - shrinkage estimates](https://discourse.datamethods.org/t/risk-adjusting-centers-shrinkage-estimates/1076)

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**Author:** [@boback](https://discourse.datamethods.org/u/boback)\
**Replies:** 3\
**Last updated:** [December 10, 2018, 11:57pm UTC](https://discourse.datamethods.org/t/risk-adjusting-centers-shrinkage-estimates/1076 "2018-12-10T23:57:38Z")

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Do people have suggestions or criticisms of how to handle risk-adjustment at hospital/center level when there are too few observations? NSQIP and CMS use shrinkage estimators but I worry this is a poor, unreliable assump…