The h-index versus the i10-index: Metrics for Academic Research Impact

Admittedly, this is likely a post that only a librarian would write. If you are reading this you are likely a librarian as well, else perhaps a youngish academic building your scholarly portfolio. Regardless, this is cool.

The h-index and the i10-index are metrics for measuring the impact of a scholar on the larger academic discussion.

We are all familiar with weighting search results by citation count, a method of ranking that assigns greater authority to results cited most frequently in other articles. But what about measuring the impact of an author rather than of an article (or other publication)?

The h-index, developed by UCSD physicist Jorge Hirsch, is one such metric. It ranks the research impact of an author (or group of authors) rather than ranking the impact of their publications. The scale is a sliding ratio of the number of publications that are each cited by more than that same number of other publications. For example, an h-index of 5 would indicate that an author has 5 publications each cited more than 5 times by other publications. This approach pays no regard to disproportionately high numbers of citations that any of those 5 publications may have. It weighs and ranks the impact of the researcher, not necessarily the impact of any particular research publication.

Determining h-index
Determining h-index
More simply, the i-10 index ranks scholars’ impact by how many of their publications have at least 10 citations in other publications. This is the index is used by Google Scholar in their ranking of scholarly impact.

According to Google Scholar, Albert Einstein has an overall h-index of 109, meaning that 109 of his publications have been cited more 109 times each. His overall i-10 index is 369, meaning that 369 of his publications have been cited at least 10 times. Compare that with Stephen Hawking who has a higher h-index of 114 but lower i10-index of 330.

h-index and i10-index for Albert Einstein
h-index and i10-index for Albert Einstein

h-index and i10-index for Stephen Hawking
h-index and i10-index for Stephen Hawking
I should urge caution on this, though, because mentioning such things in the presence of a librarian will likely result in a disturbingly enthusiastic conversation.

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