Bibliometric Indicators
h-index
The h-index is an indicator that measures both the productivity and the impact of a researcher’s publications.
- A researcher has an h-index of value h if h of their articles have each been cited at least h times.
- Example: An h-index of 10 means that 10 articles have each been cited at least 10 times.
Key points:
- Reflects both the quantity and the quality of publications.
- Limitation: it is not sensitive to highly cited papers beyond h.
g-index
The g-index is an alternative to the h-index that places greater emphasis on highly cited articles.
- A researcher has a g-index of value g if the top g cited articles together have received at least g² citations.
- Example: A g-index of 10 means that the 10 most cited articles together received at least 100 citations.
Key points:
- Highlights publications with strong impact.
- Favors researchers with highly cited work.
H1 norm
The H1 norm adjusts the h-index by accounting for co-authorship.
- Each article contributes in proportion to the inverse of the number of co-authors (1/n, where n is the number of co-authors).
Key points:
- Prevents papers with many co-authors from inflating a researcher’s h-index.
- Offers a fairer estimate of individual contribution.
H1 annual
The H1 annual is a time-normalized version of H1 norm that divides this metric by the number of years of academic activity.
- Formula: H1 norm divided by the number of active academic years.
Key points:
- Makes it easier to compare researchers with careers of different lengths.
- Useful for evaluating average yearly impact.
HA index
The HA index is a weighted version of the h-index that also considers the number of citations per article.
- Formula: each article included in the h-index calculation is weighted by its citation count.
Key points:
- Adds nuance to the h-index by accounting for citation intensity.
- Helps distinguish between researchers with the same h-index but different citation profiles.