SectionDefinition

Most citation metrics capture only one thing. Total citations reward a single blockbuster paper; paper count rewards volume regardless of quality. The h-index was designed to balance both at once.

It answers a specific question: how many of your papers have been cited at least that many times? Because a paper only joins your “h-core” once it clears the rising threshold, the index resists distortion from either one mega-cited paper or a long tail of uncited ones. That blend of output and impact is why hiring panels, funders, and ranking systems adopted it so quickly.

SectionWalk down the list

Worked example: how the h-index is read off a citation list 52 1 33 2 18 3 12 4 9 5 7 6 4 7 2 8 1 9 h = 6 6 papers, each ≥ 6 cites Each paper ranked from most-cited (left) to least-cited (right)

SectionThe shortcut

h such that your h -th most-cited paper has at least h citations. Google Scholar, Scopus, and Web of Science all compute this automatically from their own citation counts.

SectionScope

Although Hirsch designed it for individual scientists, the same formula is applied to larger units. A journal h-index counts the journal’s articles cited at least h times; SCImago reports this for every indexed title. Institutions and even whole countries are ranked the same way.

The interpretation never changes — only the set of papers being counted does.

SectionBenchmarks

There is no universal cutoff, and anyone who quotes one without naming a field is guessing. The single biggest factor is discipline : molecular biology and medicine cite heavily and produce high h-indices, while mathematics and many humanities fields cite slowly, so a “low” number there can represent elite work.

Key Takeaways

• The h-index measures both productivity and citation impact.
• An h-index of h means h papers have h+ citations each.
• What counts as ‘good’ depends on field and career stage.
• Google Scholar, Scopus, and Web of Science report different values.

FAQPeople also ask

What is a good h-index for a PhD student?

An h-index of 1–5 is typical for a PhD student or early postdoc.

Can the h-index go down?

No, the h-index never decreases.

Is the h-index the same in Google Scholar and Scopus?

No. Google Scholar usually gives the highest h-index.

Does the h-index apply to journals?

Yes. A journal’s h-index counts how many of its articles have been cited at least that many times.

SourcesReferences & further reading

• Jorge Hirsch (2005). PNAS.
• Google Scholar Metrics
• Clarivate JCR