[Statlist] Research Seminar in Statistics | *FRIDAY 28 November 2025* | GSEM, University of Geneva

[gsem-support-instituts]

Dear all,

We are pleased to invite you to our next Research Seminar, organized by Professor Davide La Vecchia on behalf of the Research Institute for Statistics and Information Science
< https://www.unige.ch/gsem/en/research/institutes/risis/team/ >.

FRIDAY 28 November 2025 at 11:15 am, Uni Mail M 5220.

Upgrading survival models with CARE
William G. UNDERWOOD, University of Cambridge, UK
< https://www.dpmms.cam.ac.uk/person/wgu21>

ABSTRACT:

Clinical risk prediction models are regularly updated as new data, often with additional covariates, become available. We propose CARE (Convex Aggregation of relative Risk Estimators) as a general approach for combining existing 'external' estimators with a new data set in a time-to-event survival analysis setting. Our method initially employs the new data to fit a flexible family of reproducing kernel estimators via penalised partial likelihood maximisation. The final relative risk estimator is then constructed as a convex combination of the kernel and external estimators, with the convex combination coefficients and regularisation parameters selected using cross-validation. We establish high-probability bounds for the L2-error of our proposed aggregated estimator, showing that it achieves a rate of convergence that is at least as good as both the optimal kernel estimator and the best external model. Empirical results from simulation studies align with the theoretical results, and we illustrate the improvements our methods provide for cardiovascular disease risk modelling. Our methodology is implemented in the Python package care-survival.

> View the Research Seminar agenda: < https://www.unige.ch/gsem/en/research/seminars/risis/ >

Regards,

 Birgit Müller-Marreros 
Assistant to the Research Institutes
gsem-support-instituts at unige.ch


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