# Do we actually need aging clocks?

## TL;DR

This paper questions the usefulness of aging clocks, arguing they lack clear definitions and fail to offer advantages over existing health prediction methods.

## Contribution

The paper introduces a critical evaluation framework to assess the practical value of aging clocks compared to established health prediction models.

## Key findings

- Aging clocks have abstract definitions and inconsistent clinical validation.
- They often ignore prediction uncertainty and lack clear advantages over expert risk scores.
- Researchers should justify the use of aging clocks over existing alternatives.

## Abstract

Aging clocks use machine learning to estimate biological age as a proxy for general health state. Here, we critically examine their practical value, highlighting fundamental challenges: abstract definitions, inconsistent clinical validation, and ignored prediction uncertainty. By comparing aging clocks with expert risk scores, direct outcome predictors, and emerging large health models, we question their benefits and encourage researchers to explicitly justify clock advantage over established alternatives, ensuring truly actionable insights.