J
Joie Ensor
Researcher at Keele University
Publications - 55
Citations - 3548
Joie Ensor is an academic researcher from Keele University. The author has contributed to research in topics: Sample size determination & Medicine. The author has an hindex of 18, co-authored 49 publications receiving 1900 citations. Previous affiliations of Joie Ensor include University of Birmingham.
Papers
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Journal ArticleDOI
Calculating the sample size required for developing a clinical prediction model.
Richard D Riley,Joie Ensor,Kym I E Snell,Frank E. Harrell,Glen P. Martin,Johannes B. Reitsma,Karel G.M. Moons,Gary S. Collins,Maarten van Smeden,Maarten van Smeden,Maarten van Smeden +10 more
TL;DR: In this article, the authors provide guidance on how to calculate the sample size required to develop a clinical prediction model.
Journal ArticleDOI
Minimum sample size for developing a multivariable prediction model: PART II ‐ binary and time‐to‐event outcomes
Richard D Riley,Kym I E Snell,Joie Ensor,Danielle L. Burke,Frank E. Harrell,Karel G.M. Moons,Gary S. Collins +6 more
TL;DR: The minimum values of n and E (and subsequently the minimum number of events per predictor parameter, EPP) should be calculated to meet the following three criteria: small optimism in predictor effect estimates as defined by a global shrinkage factor of ≥0.9, aim to reduce overfitting conditional on a chosen p, and require prespecification of the model's anticipated Cox‐Snell R2.
Journal ArticleDOI
A guide to systematic review and meta-analysis of prognostic factor studies.
Richard D Riley,Karel G.M. Moons,Kym I E Snell,Joie Ensor,Lotty Hooft,Douglas G. Altman,Jill A. Hayden,Gary S. Collins,Thomas P. A. Debray +8 more
TL;DR: Systematic reviews and meta-analyses are needed that summarise the evidence about the prognostic value of particular factors and the key steps involved in this review process are described.
Journal ArticleDOI
External validation of clinical prediction models using big datasets from e-health records or IPD meta-analysis: opportunities and challenges
Richard D Riley,Joie Ensor,Kym I E Snell,Thomas P. A. Debray,Doug G Altman,Karel G.M. Moons,Gary S. Collins +6 more
TL;DR: Novel opportunities for external validation in big, combined datasets in e-health records and individual participant data meta-analysis are illustrated, drawing attention to methodological challenges and reporting issues.
Journal ArticleDOI
Meta-analysis using individual participant data: one-stage and two-stage approaches, and why they may differ.
TL;DR: This tutorial paper outlines the key statistical methods for one‐stage and two‐stage IPD meta‐analyses, and provides 10 key reasons why they may produce different summary results, and explains that most differences arise because of different modelling assumptions.