Cited by 666Statistical Methods in EpidemiologyStatistical Methods and InferenceStatistical Methods in Clinical Trials

Sample size considerations for the external validation of a multivariable prognostic model: A resampling study

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Collins, Gary S., Ogundimu, Emmanuel O., Altman, Douglas G.·2016·Statistics in Medicine

Abstract

After developing a prognostic model, it is essential to evaluate the performance of the model in samples independent from those used to develop the model, which is often referred to as external validation. However, despite its importance, very little is known about the sample size requirements for conducting an external validation. Using a large real data set and resampling methods, we investigate the impact of sample size on the performance of six published prognostic models. Focussing on unbiased and precise estimation of performance measures (e.g. the c ‐index, D statistic and calibration), we provide guidance on sample size for investigators designing an external validation study. Our study suggests that externally validating a prognostic model requires a minimum of 100 events and ideally 200 (or more) events. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

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  1. [40]Choodari‐Oskooei B, Royston P, Parmar MK. A simulation study of predictive ability measures in a survival model I: Explained variation measures. Statistics in Medicine 2011; 31: 2644– 2659. 22764064

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Authors
Collins, G. S., Ogundimu, E. O., & Altman, D. G.
Affiliations
  • Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre University of Oxford Windmill Road Oxford OX3 7LD U.K.
  • University of Oxford (GB)
Venue
Statistics in Medicine
Publisher
Wiley
Published
2015-11-09
Volume
35
Issue
2
Pages
214-226
ISSN
  • 0277-6715 (ISSN-L)
  • 1097-0258
OpenAlex
W2122892545
Cited by
665
References
56
Citations by year
2026: 51 · 2025: 87 · 2024: 77 · 2023: 60 · 2022: 89 · 2021: 90 · 2020: 74 · 2019: 51 · 2018: 38 · 2017: 24 · 2016: 23
FWCI
25.28
Type
journal article
Language
en
Open access
Locations
  • Statistics in Medicine (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Durham Research Online (Durham University) (publishedVersion, other-oa)
  • Durham Research Online (Durham University) (acceptedVersion, other-oa)
  • Durham Research Online (Durham University) (submittedVersion, cc-by)
  • Northumbria Research Link (Northumbria University) (submittedVersion)
  • University of Birmingham Research Portal (University of Birmingham) (submittedVersion)
Funders
  • Medical Research Council (G1100513)
  • Medical Research Council Prognosis Research Strategy (PROGRESS) Partnership (G0902393/99558)
Topics
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Epidemiology
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods and Inference
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
Keywords
external validation, sample size, resampling, concordance index, calibration, D-statistic, event counts, model performance estimation
MeSH terms
Cardiovascular Diseases, Diabetes Mellitus, Type 2, Humans, Prognosis, Risk Factors, Models, Statistical, Multivariate Analysis, Databases, Factual, Sample Size, Validation Studies as Topic, Biostatistics

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