The creation of researcher rankings, the allocation of grants or prestigious positions – all these tasks require an indicator that can be used to objectively assess researchers' productivity. One of the most universal tools for this purpose is the h-index. This indicator is used to assess both individual researchers and entire institutions. How can it be calculated correctly? What data are required to do so? Let us take a closer look in today's article.
What data are used to calculate the h-Index?
The h-index is considered one of the more objective indicators for assessing researchers' productivity for a reason. The point is that other metrics, including the citation count (the total number of citations received by all publications) and average citation count (the number of citations divided by the number of articles), can easily be distorted by the influence of a single highly cited paper.
For example, if a researcher has five articles, four of which have no citations at all, while just one has 150 citations, this disparity will have a significant impact on the final value of both indicators, even though the researcher's actual, consistent contribution to science is much more modest.
The h-index was developed to avoid this subjectivity and to demonstrate the actual level of impact of a researcher's publications within the academic community. Its calculation requires data on the total number of the author's publications and the number of citations received by each publication separately. With these data, the indicator can be calculated independently using a fairly simple formula.
How to calculate the h-Index manually?
A researcher's h-index is equal to h if h of their publications have each been cited at least h times, while the remaining publications have been cited fewer than h times. This is the formula that can be used to determine the indicator. How does it work?
Step-by-step algorithm:
- Compile a complete list of your publications.
- Determine the number of citations for each publication.
- Arrange the publications in descending order of citation count.
- Number the publications.
- Find the last publication in the list whose position does not exceed its number of citations – this is your h-index.
Example of an H-Index Calculation
A researcher has 7 publications with the following numbers of citations:
| No. | Publication | Citations |
|---|---|---|
| 1 | A | 19 |
| 2 | B | 14 |
| 3 | C | 9 |
| 4 | D | 7 |
| 5 | E | 4 |
| 6 | F | 2 |
| 7 | G | 0 |
Publication No. 4 has seven citations, and its position in the list (4) is lower than the number of citations (7); therefore, the condition is met. However, publication No. 5 has only four citations. Since its position in the list (5) exceeds this number, the condition is no longer met. Therefore, the h-index is 4.
Where can you find your h-Index and publication data?
To find out your indicator, you do not necessarily have to calculate it manually. There are three main scientometric platforms that provide an automatic h-index calculation; however, each of them determines the indicator somewhat differently.
In Scopus, the relevant information can be found in the Author Profile section. This section displays the author's list of publications, the number of citations for each publication, and the h-index calculated based on the materials indexed by the database.
Web of Science operates on a similar principle through the author's Researcher Profile. However, the system only takes into account articles from journals indexed in this database. Therefore, the indicator calculated in Web of Science may differ from the one calculated by Scopus.
Google Scholar, by contrast, covers a much broader range of sources, including preprints, books and conference materials. Researchers create and maintain their author profiles themselves, after which the system automatically calculates the h-index based on the publications added to the profile.
It is precisely because of these differences in coverage that the h-index for the same researcher may differ across the three systems. Therefore, before carrying out a calculation, it is worth clarifying which database's information is required (for example, for a grant application, a position or an assessment).
The exact calculation of the h-index depends on a number of factors: the choice of database, the completeness of the publication list, as well as the accuracy of the citations taken into account. Typical errors can only be avoided and an accurate result obtained by carefully following each stage of the calculation. This approach allows researchers to use their h-index confidently in pursuit of their academic goals.
If you are experiencing difficulties in increasing your h-index, contact Scientific Publications. Our specialists will audit your author profiles and develop an individual strategy for improving your indicator. Would you like to receive a free consultation? Fill in the form below, and our manager will contact you shortly. Together towards new academic achievements!
