Events per variable (EPV) and the relative performance of different strategies for estimating the out-of-sample validity of logistic regression models, Stat Methods Med Res 2017
Substantial effective sample sizes were required for external validation studies of predictive logistic regression models, J Clin Epidemiol 2005 and a confirmation that at least 100 events are desired:
Sample size considerations for the external validation of a multivariable prognostic model: a resampling study, Stat Med 2016
Validation of prediction models: examining temporal and geographic stability of baseline risk and estimated covariate effects, BMC Diagnostic and Prognostic Research 2017
Geographic and temporal validity of prediction models: different approaches were useful to examine model performance. J Clin Epidemiol 2016
Empirical illustration of validation in a multi-cohort setting (IPD-MA):
Comparison of Prediction Models for Lynch Syndrome Among Individuals With Colorectal Cancer, JNCI 2016
GUSTO-I experience Internal validation of predictive models: efficiency of some procedures for logistic regression analysis, J Clin Epidemiol 2001 and extension: validation in small samples is unreliable
Small validation samples lead to unstable estimates of performance of prediction models, J Clin Epidemiol 2017
A proposal for a new concordance measure:
A new concordance measure for risk prediction models in external validation settings, Stat Med 2016
External validity of risk models: Use of benchmark values to disentangle a case-mix effect from incorrect coefficients, Am J Epidemiol 2010
A proposal for calibration measures, which is central to consider at validation:
A calibration hierarchy for risk models was defined: from utopia to empirical data, J Clin Epidemiol 2016
Graphical assessment of internal and external calibration of logistic regression models by using loess smoothers, Stat Med 2014
Prediction models need appropriate internal, internal-external, and external validation, J Clin Epidemiol 2016
A new framework to enhance the interpretation of external validation studies of clinical prediction models, J Clin Epidemiol 2015
Towards better clinical prediction models: seven steps for development and an ABCD for validation, Eur Heart J 2014
Assessing the performance of prediction models: a framework for traditional and novel measures, Epidemiology 2010
covers both development and validation studies:
Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis (TRIPOD): explanation and elaboration, Ann Intern Med 2015