Comment on "Average Hazard as Harmonic Mean" by Chiba

TL;DR

This paper defends the Kaplan-Meier plug-in estimator for average hazard estimation, clarifying its interpretation and demonstrating its reliability through simulations, despite recent critiques suggesting limitations.

Contribution

It provides a detailed rebuttal to Chiba's critique, supporting the estimator's validity and offering clarification on its proper use and interpretation.

Findings

Simulation studies show reliable estimates across various truncation times

The Kaplan-Meier plug-in estimator remains valid even in small samples

Clarifies the interpretation and application of the average hazard estimator

Abstract

In a recent article published in Pharmaceutical Statistics, Chiba proposed a reinterpretation of the average hazard as a harmonic mean of the hazard function and questioned the validity of the Kaplan-Meier plug-in estimator when the truncation time does not coincide with an observed event time. In this commentary, we examine the arguments presented and highlight several points that warrant clarification. Through simulation studies, we further show that the plug-in estimator provides reliable estimates across a range of truncation times, even in small samples. These support the continued utilization of the Kaplan-Meier plug-in estimator for the average hazard and help clarify its proper interpretation and implementation.