The inconsistency of the h-index

TL;DR

This paper critically examines the h-index, revealing its counterintuitive behavior and inconsistencies in ranking scientists, and proposes the highly cited publications indicator as a more reliable alternative.

Contribution

The paper provides a theoretical critique of the h-index and introduces the highly cited publications indicator as a better measure of scientific impact.

Findings

The h-index can produce inconsistent scientist rankings.

The h-index behaves counterintuitively in certain cases.

The highly cited publications indicator avoids these inconsistencies.

Abstract

The h-index is a popular bibliometric indicator for assessing individual scientists. We criticize the h-index from a theoretical point of view. We argue that for the purpose of measuring the overall scientific impact of a scientist (or some other unit of analysis) the h-index behaves in a counterintuitive way. In certain cases, the mechanism used by the h-index to aggregate publication and citation statistics into a single number leads to inconsistencies in the way in which scientists are ranked. Our conclusion is that the h-index cannot be considered an appropriate indicator of a scientist's overall scientific impact. Based on recent theoretical insights, we discuss what kind of indicators can be used as an alternative to the h-index. We pay special attention to the highly cited publications indicator. This indicator has a lot in common with the h-index, but unlike the h-index it does not produce inconsistent rankings.