ArticleThe R journal2022
Power and Sample Size for Longitudinal Models in R - The longpower Package and Shiny App.
Article in The R journal, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 29 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
29 citing papers in PubMed.
- Validation of a novel cognitive-functional outcome measure optimized for early Alzheimer's Disease: Evidence from the VIVA-MIND trial.The journal of prevention of Alzheimer's disease · 2026Trial
- Efficacy of the Flo App in Improving Health Literacy, Menstrual and General Health, and Well-Being in Women: Pilot Randomized Controlled Trial.JMIR mHealth and uHealth · 2024Trial
- Article
- Perinatal mental health and reproductive behavior among women in wartime Ukraine: a cohort study protocol.Frontiers in psychiatry · 2026Article
- Brain atrophy staging in spinocerebellar ataxia type 3 for clinical prognosis and trial enrichment.EBioMedicine · 2026Article
- Brain age gap as predictor of disease progression in Parkinson's disease.NPJ Parkinson's disease · 2025Article
- Electroencephalography evidence of functional connectivity modulation and its correlation with bimanual visuomotor learning.Cognitive neurodynamics · 2025Article
- A digital motor score for sensitive detection of progression in Huntington's disease.Brain : a journal of neurology · 2025Article
- Objective monitoring of motor symptom severity and their progression in Parkinson's disease using a digital gait device.Scientific reports · 2025Article
- BrainAge moderates associations between Alzheimer's disease biomarkers and cognitive decline: a meta-analysis across A4/LEARN, HABS and ADNI cohorts.medRxiv : the preprint server for health sciences · 2025Article
- STORCH Brazil: multicenter cohort study protocol to investigate neurodevelopmental paths and functioning in infants exposed to STORCH in Brazil.BMC pediatrics · 2025Article
- Reliability of structural brain change in cognitively healthy adult samples.bioRxiv : the preprint server for biology · 2025Article
- Study protocol for the randomized controlled trial of EMBOLDEN: a multifaceted intervention aimed at Enhancing physical and community MoBility in OLDEr adults with health inequities using commuNity co-design.Frontiers in public health · 2025Article
- Article
- Reliability of structural brain change in cognitively healthy adult samples.Imaging neuroscience (Cambridge, Mass.) · 2025Article
- Power and sample size for reversible linear mixed models with clustering and longitudinality: GLIMMPSE Version 3.PloS one · 2025Article
- A digital dashboard for reporting mental, neurological and substance use disorders in Nairobi, Kenya: Implementing an open source data technology for improving data capture.PLOS digital health · 2024Article
- Progression subtypes in Parkinson's disease identified by a data-driven multi cohort analysis.NPJ Parkinson's disease · 2024Article
- Cerebral perivascular spaces as predictors of dementia risk and accelerated brain atrophy.medRxiv : the preprint server for health sciences · 2024Article
- Vascular risk burden is a key player in the early progression of Alzheimer's disease.Neurobiology of aging · 2024Article
Corrections and comments
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Authors and funding
2 authors.
Funding
Abstract
Longitudinal studies are ubiquitous in medical and clinical research. Sample size computations are critical to ensure that these studies are sufficiently powered to provide reliable and valid inferences. There are several methodologies for calculating sample sizes for longitudinal studies that depend on many considerations including the study design features, outcome type and distribution, and proposed analytical methods. We briefly review the literature and describe sample size formulas for continuous longitudinal data. We then apply the methods using example studies comparing treatment versus control groups in randomized trials assessing treatment effect on clinical outcomes. We also introduce a Shiny app that we developed to assist researchers with obtaining required sample sizes for longitudinal studies by allowing users to enter required pilot estimates. For Alzheimer's studies, the app can estimate required pilot parameters using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Illustrative examples are used to demonstrate how the package and app can be used to generate sample size and power curves. The package and app are designed to help researchers easily assess the operating characteristics of study designs for Alzheimer's clinical trials and other research studies with longitudinal continuous outcomes. Data used in preparation of this article were obtained from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database (adni.loni.usc.edu).
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.