Skip to Main Content

Publication Metrics

Responsible metrics- key messages on researcher impact

- DORA: "Use a range of article metrics and indicators on personal/supporting statements, as evidence of the impact of individual published articles and other research outputs"

 

- Leiden Manifesto: "Base assessment of individual researchers on a qualitative judgement of their portfolio"

 

- The Metric Tide: "performance-based control mechanisms are increasingly used outside their original context of evaluation ... leading to an inappropriate emphasis on individual measures such as the h-index."

H-index

Invented by Jorge Hirsch in 2005, the H-index quantifies the output of an individual researcher. It addresses problems with using total number of articles or total citations as an indicator of impact and it  can be a useful metric because it discounts the disproportionate weight of highly cited papers. 

It is worked out by ranking the researcher’s papers in descending order of how many times each has been cited. The value of H is equal to the number of papers in the list that have that same number or more citations.

For example:

Title 1  cited 1177 times

Title 2   cited 721 times

Title 3   cited 717 times

…

Title 55  cited 71 times

Title 66  cited 69 times

Title 67  cited 67 times

------------------------------------------------------------------ h index = 67

Title 68  cited 67 times

A researcher's H-index may vary from one database to another. Scopus, Web of Science and Google Scholar, for example, all look at slightly different sets of publications, and consequently citation counts will be different. 

The H-index is also biased against researchers with a short career and it does not take into account self-cites, review articles, or co-authors

Like many other metrics, it can only be used to compare authors working in the same fields.

 

M-quotient

This is a variant of the H-index. It aims to address issue of H-index bias against early career researchers.

The M-quotient is calculated by dividing the h-index by the number of research active years (taken from publication date of first article).

For example

Researcher

H-index

Years active

M-quotient

a

50

25

2

b

30

10

3

The issues with this are: the first publication may well have been a small publication as a co-author, long before the researcher started publishing more regularly. It discriminates against people who have taken career breaks, or work part time, and therefore it is more likely to adversely impact on women.

 

Alternatives to the H-index

The h-index is not a useful metric for early career researchers, amongst other criticisms of its usefulness. Some alternative metrics you might want to consider include:

  • Publication and/or citation count
  • Citation impact (Mean Citations per publication)
  • % Outputs in Top percentiles
  • % Outputs in Top Journals
  • % Outputs cited