Position: Stop Chasing the C-index when Evaluating Survival Analysis Models

Fuente: arXiv
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Main Authors: Lillelund, Christian Marius, Qi, Shi-ang, Greiner, Russell, Pedersen, Christian Fischer
Format: Preprint
Published: 2025
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author Lillelund, Christian Marius
Qi, Shi-ang
Greiner, Russell
Pedersen, Christian Fischer
author_facet Lillelund, Christian Marius
Qi, Shi-ang
Greiner, Russell
Pedersen, Christian Fischer
contents The current state of evaluation in survival analysis is plagued by the persistent use of evaluation metrics in ways that are misaligned with the stated modeling objective. In addition, many such evaluations are based on censoring assumptions that are left implicit or unjustified. This means that the reported performance can be misleading and may fail to answer the scientific or modeling question the evaluation was intended to address. In this position paper, we critically examine evaluation practices in survival analysis and highlight how censoring makes evaluation fundamentally different from standard regression or classification. We place particular focus on concordance-based measures, such as the C-index, which we show are heavily overused in the literature. To help identify appropriate metrics, we propose a set of key desiderata and introduce a double-helix ladder, in which valid evaluation requires alignment between metric and modeling assumptions. Through controlled experiments, we show that violations of this alignment can lead to misleading model comparisons. We conclude by providing practical guidance on how to evaluate a survival model.
format Preprint
id arxiv_https___arxiv_org_abs_2506_02075
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Position: Stop Chasing the C-index when Evaluating Survival Analysis Models
Lillelund, Christian Marius
Qi, Shi-ang
Greiner, Russell
Pedersen, Christian Fischer
Methodology
Machine Learning
The current state of evaluation in survival analysis is plagued by the persistent use of evaluation metrics in ways that are misaligned with the stated modeling objective. In addition, many such evaluations are based on censoring assumptions that are left implicit or unjustified. This means that the reported performance can be misleading and may fail to answer the scientific or modeling question the evaluation was intended to address. In this position paper, we critically examine evaluation practices in survival analysis and highlight how censoring makes evaluation fundamentally different from standard regression or classification. We place particular focus on concordance-based measures, such as the C-index, which we show are heavily overused in the literature. To help identify appropriate metrics, we propose a set of key desiderata and introduce a double-helix ladder, in which valid evaluation requires alignment between metric and modeling assumptions. Through controlled experiments, we show that violations of this alignment can lead to misleading model comparisons. We conclude by providing practical guidance on how to evaluate a survival model.
title Position: Stop Chasing the C-index when Evaluating Survival Analysis Models
topic Methodology
Machine Learning
url https://arxiv.org/abs/2506.02075