Cited by 243Statistical Methods in EpidemiologyAdvanced Causal Inference TechniquesMeta-analysis and systematic reviews

External Validity of Risk Models: Use of Benchmark Values to Disentangle a Case-Mix Effect From Incorrect Coefficients

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Vergouwe, Y., Moons, K. G. M., Steyerberg, E. W.·2010·American Journal of Epidemiology

Abstract

Various performance measures related to calibration and discrimination are available for the assessment of risk models. When the validity of a risk model is assessed in a new population, estimates of the model's performance can be influenced in several ways. The regression coefficients can be incorrect, which indeed results in an invalid model. However, the distribution of patient characteristics (case mix) may also influence the performance of the model. Here the authors consider a number of typical situations that can be encountered in external validation studies. Theoretical relations between differences in development and validation samples and performance measures are studied by simulation. Benchmark values for the performance measures are proposed to disentangle a case-mix effect from incorrect regression coefficients, when interpreting the model's estimated performance in validation samples. The authors demonstrate the use of the benchmark values using data on traumatic brain injury obtained from the International Tirilazad Trial and the North American Tirilazad Trial (1991-1994).

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  • Interpretation of validation study results is often difficult because changes in prediction model performance are likely due to sampling error, differences in predictor effects, and/or differences in patient spectrum.

    “Unfortunately, the interpretation of validation study results is often difficult, as changes in prediction model performance are likely to occur due to sampling error, differences in predictor effects, and/or differences in patient spectrum.”
  • A model's discrimination performance tends to deteriorate when it is applied to populations or subgroups with a more homogeneous case-mix, as there is less separation of predicted risks across individuals.

    “For instance, it is well known that a model’s discrimination performance tends to deteriorate when it is applied to populations or subgroups with a more homogeneous case-mix, as there is less separation of predicted risks across individuals.”
  • An additional advantage of IPD is that it becomes possible to adjust discrimination performance for (variation in) subject-level covariates, and thus to gain more understanding in sources of between-study heterogeneity.

    “An additional advantage of IPD is that it becomes possible to adjust discrimination performance for (variation in) subject-level covariates, and thus to gain more understanding in sources of between-study heterogeneity.9,10,26,68”
  • Common sources of heterogeneity are differences in study characteristics, differences in study quality, or differences in baseline risk across the validation studies.

    “Common sources of heterogeneity are differences in study characteristics,62 differences in study quality, or differences in baseline risk across the validation studies.9,10”

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Research works printed but not linked: 1

  1. Steyerberg EW, Eijkemans MJ, Harrell FE Jr, et al. Prognostic modelling with logistic regression analysis: a comparison of selection and estimation methods in small data sets. Stat Med. 2000;19(8):1059-1079.

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Authors
Vergouwe, Y., Moons, K. G. M., & Steyerberg, E. W.
Affiliations
University Medical Center Utrecht (NL)
Corresponding author
Vergouwe, Y.
Venue
American Journal of Epidemiology
Published
2010-08-31
Volume
172
Issue
8
Pages
971-980
ISSN
  • 0002-9262 (ISSN-L)
  • 1476-6256
OpenAlex
W2104039704
Cited by
243
References
38
Citations by year
2026: 15 · 2025: 11 · 2024: 13 · 2023: 13 · 2022: 21 · 2021: 24 · 2020: 16 · 2019: 20 · 2018: 17 · 2017: 15 · 2016: 15 · 2015: 14 · 2014: 21 · 2013: 11 · 2012: 12
FWCI
7.62
Type
journal article
Language
en
Open access
Locations
  • American Journal of Epidemiology (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • EUR Research Repository (Erasmus University Rotterdam) (publishedVersion)
  • EUR Research Repository (Erasmus University Rotterdam) (submittedVersion)
  • RePub (Erasmus University Rotterdam) (submittedVersion, other-oa)
  • RePub (Erasmus University Rotterdam) (submittedVersion)
Funders
  • Nederlandse Organisatie voor Wetenschappelijk Onderzoek (016.046.360)
  • National Institute of Neurological Disorders and Stroke (NS-42691, R01NS042691)
Topics
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Epidemiology
  • Physical Sciences › Mathematics › Statistics and Probability › Advanced Causal Inference Techniques
  • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
Keywords
risk model, generalizability, external validation, benchmark values, calibration, discrimination (statistics), regression coefficients, traumatic brain injury, model performance measures
MeSH terms
Computer Simulation, Diagnosis-Related Groups, Humans, Risk Factors, Models, Statistical, Benchmarking

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