# research methods

**URL:** https://discourse.datamethods.org/c/resmeth/12.md?page=2

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**Page:** 3

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## [Calculate incidence rate after adjustment](https://discourse.datamethods.org/t/calculate-incidence-rate-after-adjustment/6580)

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**Author:** [@Hanis\_Kadir](https://discourse.datamethods.org/u/Hanis_Kadir)\
**Replies:** 10\
**Last updated:** [March 19, 2024, 10:12pm UTC](https://discourse.datamethods.org/t/calculate-incidence-rate-after-adjustment/6580 "2024-03-19T22:12:29Z")

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Hi all, I would like to replicate the following study using my local cohort. i.e. to assess the absolute risk of bullous pemphigoid (BP) for patients initiated with DPP4 vs the comparator, Sulfonylureaurea drugs. Lee H…

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## [Is Lithium Equivalent to Lecanemab in Slowing cognitive decline in Alzheimer's Disease?](https://discourse.datamethods.org/t/is-lithium-equivalent-to-lecanemab-in-slowing-cognitive-decline-in-alzheimers-disease/7936)

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**Author:** [@llynn](https://discourse.datamethods.org/u/llynn)\
**Replies:** 0\
**Last updated:** [February 23, 2024, 12:17am UTC](https://discourse.datamethods.org/t/is-lithium-equivalent-to-lecanemab-in-slowing-cognitive-decline-in-alzheimers-disease/7936 "2024-02-23T00:17:35Z")

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Massive hype (and real hope) exists relevant Lecanemab, the newly approved (July 2023) medication for Alzheimer’s disease. Earlier amyloid-beta monoclonal antibodies largely failed but Lecanemab demonstrated a statistica…

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## [Review of Trial at the Center of the Firestorm Over Early Connection of Patients to Ventilators during the Pandemic](https://discourse.datamethods.org/t/review-of-trial-at-the-center-of-the-firestorm-over-early-connection-of-patients-to-ventilators-during-the-pandemic/6926)

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**Author:** [@llynn](https://discourse.datamethods.org/u/llynn)\
**Replies:** 34\
**Last updated:** [February 16, 2024, 1:16am UTC](https://discourse.datamethods.org/t/review-of-trial-at-the-center-of-the-firestorm-over-early-connection-of-patients-to-ventilators-during-the-pandemic/6926 "2024-02-16T01:16:21Z")

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Presently there is a disturbing and growing outcry in social media that physicians willfully placed patients with COVID pneumonia on invasive mechanical ventilators, negligently contributing to their death. This misgui…

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## [RCT: protocol deviation and implications for analysis](https://discourse.datamethods.org/t/rct-protocol-deviation-and-implications-for-analysis/7691)

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**Author:** [@Erin1](https://discourse.datamethods.org/u/Erin1)\
**Replies:** 6\
**Last updated:** [February 16, 2024, 1:39pm UTC](https://discourse.datamethods.org/t/rct-protocol-deviation-and-implications-for-analysis/7691 "2024-02-16T13:39:29Z")

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Please consider how you would respond to the following situation as the statistician on a randomized controlled trial. Participants are randomly assigned to treatment or control group. The baseline assessment occurs jus…

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## [Handling missing continuous data due to death](https://discourse.datamethods.org/t/handling-missing-continuous-data-due-to-death/7437)

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**Author:** [@timdisher](https://discourse.datamethods.org/u/timdisher)\
**Replies:** 7\
**Last updated:** [February 8, 2024, 9:57pm UTC](https://discourse.datamethods.org/t/handling-missing-continuous-data-due-to-death/7437 "2024-02-08T21:57:35Z")

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Hi everyone, I work in neonatal research where it’s common to have interventions that have large benefits to the in-hospital course but heterogeneous outcomes in terms of development. So for example we can reduce lung d…

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## [Sample Size calculation - "subgroup hypothesis", Guidance needed](https://discourse.datamethods.org/t/sample-size-calculation-subgroup-hypothesis-guidance-needed/7381)

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**Author:** [@JuliaRose](https://discourse.datamethods.org/u/JuliaRose)\
**Replies:** 2\
**Last updated:** [February 4, 2024, 2:00pm UTC](https://discourse.datamethods.org/t/sample-size-calculation-subgroup-hypothesis-guidance-needed/7381 "2024-02-04T14:00:33Z")

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Hey there, I hope it is not a too dumb question, but until last week I thought I have understood the main principles of sample size calculation. Now I got introduced into a project and have to do the sample size calcula…

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## [ITT analysis population - RCT](https://discourse.datamethods.org/t/itt-analysis-population-rct/7064)

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**Author:** [@rameelac](https://discourse.datamethods.org/u/rameelac)\
**Replies:** 6\
**Last updated:** [February 3, 2024, 12:57pm UTC](https://discourse.datamethods.org/t/itt-analysis-population-rct/7064 "2024-02-03T12:57:49Z")

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I am working on a multi-site randomized, placebo-controlled, double-blind, parallel-design trial. The trial population will be made up of two cohorts: cohort 1 who meet a specific inclusion criteria (N) and cohort 2 who …

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## [Practicalities of using Markov Longitudinal Ordinal Models in Cardiovascular Outcome Trials](https://discourse.datamethods.org/t/practicalities-of-using-markov-longitudinal-ordinal-models-in-cardiovascular-outcome-trials/7237)

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**Author:** [@mshunshin](https://discourse.datamethods.org/u/mshunshin)\
**Replies:** 5\
**Last updated:** [January 25, 2024, 6:49pm UTC](https://discourse.datamethods.org/t/practicalities-of-using-markov-longitudinal-ordinal-models-in-cardiovascular-outcome-trials/7237 "2024-01-25T18:49:41Z")

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Cardiovascular outcome trials often have a composite outcome - e.g. Death, Stroke, MI, and Hospitalisation - lumped all together than analysed as time to event. More recently, the “win ratio” has started to be advocated…

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## [Mixed vs Random Effects ICC](https://discourse.datamethods.org/t/mixed-vs-random-effects-icc/1215)

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**Author:** [@Granville\_Matheson](https://discourse.datamethods.org/u/Granville_Matheson)\
**Replies:** 13\
**Last updated:** [January 23, 2024, 8:08pm UTC](https://discourse.datamethods.org/t/mixed-vs-random-effects-icc/1215 "2024-01-23T20:08:08Z")

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Hi folks. I’m looking for a little bit of help with different measures of reliability, and test-retest reliability specifically. I would be thrilled if anyone could help. And if anyone finds it easier to explain using R…

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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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## [Calculate event/total of an outcome that is reported as Hazard Ratio (95% CI, p-value)](https://discourse.datamethods.org/t/calculate-event-total-of-an-outcome-that-is-reported-as-hazard-ratio-95-ci-p-value/7357)

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**Author:** [@ahmed\_elkoumi](https://discourse.datamethods.org/u/ahmed_elkoumi)\
**Replies:** 1\
**Last updated:** [January 10, 2024, 7:27am UTC](https://discourse.datamethods.org/t/calculate-event-total-of-an-outcome-that-is-reported-as-hazard-ratio-95-ci-p-value/7357 "2024-01-10T07:27:37Z")

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I am conducting a meta-analysis. One of the included papers has baseline characteristics of an outcome in intervention and control groups (No.). However, in reporting the findings they reported the event/total in the int…

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## [Language for communicating frequentist results about treatment effects](https://discourse.datamethods.org/t/language-for-communicating-frequentist-results-about-treatment-effects/934)

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**Author:** [@f2harrell](https://discourse.datamethods.org/u/f2harrell)\
**Replies:** 200\
**Last updated:** [January 9, 2024, 11:32am UTC](https://discourse.datamethods.org/t/language-for-communicating-frequentist-results-about-treatment-effects/934 "2024-01-09T11:32:21Z")

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Correct interpretation of p \> 0.05: The current sample size did not yield sufficient evidence to reject, at the incredibly arbitrary 0.05 level, the supposition that the treatment does nothing, assuming data model M (de…

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## [Substituting treatment arm with drug exposure (continuous variable) in RCT](https://discourse.datamethods.org/t/substituting-treatment-arm-with-drug-exposure-continuous-variable-in-rct/7327)

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**Author:** [@feizuo](https://discourse.datamethods.org/u/feizuo)\
**Replies:** 10\
**Last updated:** [January 8, 2024, 10:19am UTC](https://discourse.datamethods.org/t/substituting-treatment-arm-with-drug-exposure-continuous-variable-in-rct/7327 "2024-01-08T10:19:09Z")

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In epilepsy trials, there often is interest in conducting a pharmacokinetic (PK) analysis by regressing the plasma concentrations of drug exposure on the primary seizure outcome/endpoint. For example, an RCT has 4 treat…

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## [Accuracy of ChatGPT on Statistical Methods](https://discourse.datamethods.org/t/accuracy-of-chatgpt-on-statistical-methods/6402)

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**Author:** [@f2harrell](https://discourse.datamethods.org/u/f2harrell)\
**Replies:** 19\
**Last updated:** [December 25, 2023, 2:07am UTC](https://discourse.datamethods.org/t/accuracy-of-chatgpt-on-statistical-methods/6402 "2023-12-25T02:07:18Z")

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OpenAI has created ChatGPT, a “chat generative pre-trained transformer” that has received extensive worldwide attention. ChatGPT has been tested in a variety of situations and has been able to achieve passing levels in …

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## [Sample size consideration for establishing a reference interval](https://discourse.datamethods.org/t/sample-size-consideration-for-establishing-a-reference-interval/2599)

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**Author:** [@EpiLearneR](https://discourse.datamethods.org/u/EpiLearneR)\
**Replies:** 10\
**Last updated:** [December 8, 2023, 5:45pm UTC](https://discourse.datamethods.org/t/sample-size-consideration-for-establishing-a-reference-interval/2599 "2023-12-08T17:45:23Z")

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is there any formula for calculation of sample size for establishing reference interval. reference levels of thyroid function tests will be different in different ethnic group. we would like to find out the reference le…

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## [Combining HR from same study sub-groups for meta-analysis](https://discourse.datamethods.org/t/combining-hr-from-same-study-sub-groups-for-meta-analysis/7262)

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**Author:** [@felippelazar](https://discourse.datamethods.org/u/felippelazar)\
**Replies:** 0\
**Last updated:** [November 28, 2023, 9:51am UTC](https://discourse.datamethods.org/t/combining-hr-from-same-study-sub-groups-for-meta-analysis/7262 "2023-11-28T09:51:39Z")

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Hi all, I’m working on a meta-analysis of randomized clinical trials in oncology and had a doubt I search the internet and could not find an adequate answer. In one of the trials (out of five total), we have only the H…

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## [Preclinical experiments analysis](https://discourse.datamethods.org/t/preclinical-experiments-analysis/7239)

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**Author:** [@valens](https://discourse.datamethods.org/u/valens)\
**Replies:** 5\
**Last updated:** [November 21, 2023, 2:40pm UTC](https://discourse.datamethods.org/t/preclinical-experiments-analysis/7239 "2023-11-21T14:40:28Z")

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Dear all, I am seeking your feedback on a series of preclinical experiments. Setting: We are conducting a three-arm therapy trial in a disease murine model. Some measurements will be taken from live subjects, while oth…

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## [Balancing potential bias with identifying enough events in observational data](https://discourse.datamethods.org/t/balancing-potential-bias-with-identifying-enough-events-in-observational-data/7162)

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**Author:** [@alizuri](https://discourse.datamethods.org/u/alizuri)\
**Replies:** 3\
**Last updated:** [November 6, 2023, 10:04pm UTC](https://discourse.datamethods.org/t/balancing-potential-bias-with-identifying-enough-events-in-observational-data/7162 "2023-11-06T22:04:23Z")

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We are designing a retrospective study using the EHR. We intend to look at the effect of ‘weight cycling’ on developing cardiometabolic disease (type 2 diabetes, MI, etc.). Weight cycling has a few definitions, but is ty…

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## [Evidence Factors](https://discourse.datamethods.org/t/evidence-factors/7158)

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**Author:** [@trumanfrancis](https://discourse.datamethods.org/u/trumanfrancis)\
**Replies:** 1\
**Last updated:** [November 1, 2023, 2:21pm UTC](https://discourse.datamethods.org/t/evidence-factors/7158 "2023-11-01T14:21:04Z")

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Is the evidence factor approach for causal inference considered useful in medical research? Paul Rosenbaum: Replication and Evidence Factors in Observational Studies - YouTube

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## [Summary Statistics vs Raw Data](https://discourse.datamethods.org/t/summary-statistics-vs-raw-data/4165)

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**Author:** [@f2harrell](https://discourse.datamethods.org/u/f2harrell)\
**Replies:** 9\
**Last updated:** [October 23, 2023, 2:32pm UTC](https://discourse.datamethods.org/t/summary-statistics-vs-raw-data/4165 "2023-10-23T14:32:24Z")

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The purpose of this topic is for clinical trialists and statisticians to discuss power, sample size, missing data-handling, and treatment \\times time interaction advantages of using longitudinal raw data in analyzing pa…

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## [Adjusting for UD in samples that are below LOD](https://discourse.datamethods.org/t/adjusting-for-ud-in-samples-that-are-below-lod/7123)

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**Author:** [@Sudhi\_Upadhyaya](https://discourse.datamethods.org/u/Sudhi_Upadhyaya)\
**Replies:** 7\
**Last updated:** [October 19, 2023, 12:49am UTC](https://discourse.datamethods.org/t/adjusting-for-ud-in-samples-that-are-below-lod/7123 "2023-10-19T00:49:36Z")

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In analyzing assay data, the steps are as follows: first , collecting urine specimens from subjects. second , these urine samples are shipped to labs that run some tests to detect the concentrations of various chemical…

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## [Regression to the mean and parallel RCTs](https://discourse.datamethods.org/t/regression-to-the-mean-and-parallel-rcts/6914)

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**Author:** [@JorgeTeixeira](https://discourse.datamethods.org/u/JorgeTeixeira)\
**Replies:** 13\
**Last updated:** [September 3, 2023, 10:59pm UTC](https://discourse.datamethods.org/t/regression-to-the-mean-and-parallel-rcts/6914 "2023-09-03T22:59:38Z")

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Dear all, I always thought that RTM was addressed by study design (RCTs) rather than statistical modeling. However this post from Solomon made me wonder about this. Is it possible to say which is more influential here (…

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## [Design of Experiments in Economics vs Medicine: a Decision Theory POV](https://discourse.datamethods.org/t/design-of-experiments-in-economics-vs-medicine-a-decision-theory-pov/6567)

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**Author:** [@R\_cubed](https://discourse.datamethods.org/u/R_cubed)\
**Replies:** 6\
**Last updated:** [July 27, 2023, 7:59pm UTC](https://discourse.datamethods.org/t/design-of-experiments-in-economics-vs-medicine-a-decision-theory-pov/6567 "2023-07-27T19:59:04Z")

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This post is inspired by the @f2harrell reference to the economist Lars P Syll’s post The Limited Value of Randomization. It is a good entry point into the criticisms of so-called “evidence based medicine” heuristics mo…

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## [What should be the denominator for an online national survey?](https://discourse.datamethods.org/t/what-should-be-the-denominator-for-an-online-national-survey/6893)

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**Author:** [@Junaid](https://discourse.datamethods.org/u/Junaid)\
**Replies:** 5\
**Last updated:** [June 27, 2023, 8:27pm UTC](https://discourse.datamethods.org/t/what-should-be-the-denominator-for-an-online-national-survey/6893 "2023-06-27T20:27:52Z")

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Dear members, I planned to conduct a prevalence survey (on a rare disease) in the general adult population in the UK. My initial plan was to distribute the survey to 6000 randomly selected addresses and also make it ava…

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## [I am doing a meta analysis of a logarthmic value: any special considerations?](https://discourse.datamethods.org/t/i-am-doing-a-meta-analysis-of-a-logarthmic-value-any-special-considerations/6901)

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**Author:** [@tominastatshole](https://discourse.datamethods.org/u/tominastatshole)\
**Replies:** 0\
**Last updated:** [June 23, 2023, 4:10pm UTC](https://discourse.datamethods.org/t/i-am-doing-a-meta-analysis-of-a-logarthmic-value-any-special-considerations/6901 "2023-06-23T16:10:04Z")

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Two main questions 1)I’m trying to do a meta analysis of a logarthmic value (decibels), any special considerations? so with the logarithmic value will the tree plot make sense visually, it not the same as an effect size…

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## [How to condunct a survival meta-analysis when the data for standard deviation ist missing?](https://discourse.datamethods.org/t/how-to-condunct-a-survival-meta-analysis-when-the-data-for-standard-deviation-ist-missing/6849)

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**Author:** [@janafvh](https://discourse.datamethods.org/u/janafvh)\
**Replies:** 1\
**Last updated:** [June 3, 2023, 11:18am UTC](https://discourse.datamethods.org/t/how-to-condunct-a-survival-meta-analysis-when-the-data-for-standard-deviation-ist-missing/6849 "2023-06-03T11:18:55Z")

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Hey there, I‘m currently working on a surivival meta-analysis and I use SPSS for my statistics. The problem is that I have a lot of data regarding mean OS / PFS, but no belonging standard deviations… does anyone have an …

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## [Capturing daily patterns in step counts](https://discourse.datamethods.org/t/capturing-daily-patterns-in-step-counts/6625)

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**Author:** [@f2harrell](https://discourse.datamethods.org/u/f2harrell)\
**Replies:** 9\
**Last updated:** [May 11, 2023, 4:01pm UTC](https://discourse.datamethods.org/t/capturing-daily-patterns-in-step-counts/6625 "2023-05-11T16:01:03Z")

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Consider Fitbit data where step counts can be recorded on a continuous basis. Computing average daily step counts and other simple measures is easy, but what if you wanted to capture time patterns including long sedenta…

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## [REDCap / R Best Practices](https://discourse.datamethods.org/t/redcap-r-best-practices/6184)

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**Author:** [@spgarbet](https://discourse.datamethods.org/u/spgarbet)\
**Replies:** 1\
**Last updated:** [April 25, 2023, 11:10pm UTC](https://discourse.datamethods.org/t/redcap-r-best-practices/6184 "2023-04-25T23:10:05Z")

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REDCap (Research Data Capture) developed at Vanderbilt University Medical Center is a widely used web-hosted research data capture and reporting tool for web data and mobile devide data entry. It is build for tightly de…

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## [Not randomized and no intervention assigned/delivered - what next?](https://discourse.datamethods.org/t/not-randomized-and-no-intervention-assigned-delivered-what-next/6601)

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**Author:** [@c\_gatto](https://discourse.datamethods.org/u/c_gatto)\
**Replies:** 3\
**Last updated:** [April 20, 2023, 1:46pm UTC](https://discourse.datamethods.org/t/not-randomized-and-no-intervention-assigned-delivered-what-next/6601 "2023-04-20T13:46:09Z")

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Good afternoon all. I’m new here!! @f2harrell thanks for the suggestion to come on in! We’ve had an unusual occurrence in relation to the deployment of a survey - and could use some advice. Here are the details of what…

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## [FDA response to Citizen Petition to include Quality of Life comparisons in RCTs](https://discourse.datamethods.org/t/fda-response-to-citizen-petition-to-include-quality-of-life-comparisons-in-rcts/6437)

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**Author:** [@karlamoPA](https://discourse.datamethods.org/u/karlamoPA)\
**Replies:** 2\
**Last updated:** [April 5, 2023, 5:34pm UTC](https://discourse.datamethods.org/t/fda-response-to-citizen-petition-to-include-quality-of-life-comparisons-in-rcts/6437 "2023-04-05T17:34:45Z")

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Copying a snippet of the FDA response to advocate’s petition (that would be me) along with links to the full text and the original petition. The issue remains. Quality of life is integral to the assessment of risk/bene…

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