What is a good h index
A simple definition of the h-index
The h-index was originally defined by J. E. Hirsch in a Proceedings of the National Academy of Sciences article as the number of papers with citation number ≥ h. An h-index of 3 hence means that the author has published at least three articles, of which each has been cited at least three times.
The h-index can also simply be determined by charting the article's citation counts. The h-index is then determined by the interception of the chart's diagonal with the citation data. In this case there are 3 papers that are above the diagonal, and hence the h-index is 3
The definition of the h-index comes with quite few desirable features:
The definition of the h-index comes with quite few desirable features:
- First, it is relatively unaffected by outliers. If e.g. the top ranked article had been cited 1,000 times, this would not change the h-index.
- Second, the h-index will generally only increase if the researcher continues to produce good work. The h-index would increase to 4 if another paper was added with 4 citations, but would not increase if papers were added with fewer citations.
- Third, the h-index will never be greater than the number of papers the author has published; to have an h-index of 20, the author must have published at least 20 articles which have each been cited at least 20 times.
A step-by-step outline how to calculate your h-index
- Step 1: List all your published articles in a table.
- Step 2: For each article gather the number it has been cited.
- Step 3: Rank the papers by the number of times they have been cited.
- Step 4: The h-index can now be inferred by finding the entry at which the rank in the list is greater than the number of citations.
Here is an example of a table where articles have been ranked by their citation count and the h-index has been inferred to be 3.Luckily, there are services like Scopus, Web of Science, and Google Scholar that can do the heavy lifting and automatically provide the citation count data and calculate the h-index.
Why it is important for your career to know about the h-index
The h-index is not something that needs to be calculated on a daily basis, but it's good to know where you are for several reasons. First, climbing the h-index ladder is something worth celebrating. If it's worth opening a bottle of champagne or just getting a cafe latte that's up to you, but seriously take your time to celebrate this achievement (there aren't that many in academia). But more importantly, the h-index is one of the measures funding agencies or the university's hiring committee calculate when you apply for a grant or a position. Given the often huge number of applications, the h-index is calculated in order to rank candidates and apply a pre-filter.
Of course, funding agencies and hiring committees do use tools for calculating the h-index, and so can you.
It is important to note that depending on the underlying data that these services have collected, your h-index might be different.
What Is a Good H-Index Required for an Academic Position?
Metrics are important. Even scholars who may not entirely agree with the ways in which academic and scientific impact is currently measured and used cannot deny that metrics play a significant role in determining who receives research grants, employment offers and desirable promotions. The h-index is only one among various kinds of metrics now applied to the research-based writing of professional scholars, but it is an increasingly significant one.
The h-index is considered preferable to metrics that measure only a researcher’s number of publications or the number of times those publications have been cited. This is because it combines the two, considering both publications and citations to arrive at a particular value. A scholar who has five publications that have been cited at least five times has an h-index of 5, whereas a scholar with ten publications that have been cited ten times has an h-index of 10. Publication and citation patterns differ markedly across disciplines and fields of study, and the expectations of hiring and funding bodies vary depending on the level and type of position and the kind and size of research project, so it is impossible to say exactly what might be considered an acceptable or competitive h-index in a given situation. H-index scores between 3 and 5 seem common for new assistant professors, scores between 8 and 12 fairly standard for promotion to the position of tenured associate professor, and scores between 15 and 20 about right for becoming a full professor. Be aware, however, that these are gross generalisations and actual figures vary enormously among disciplines and fields: there are, for instance, many full professors, deans and chancellors with very low h-index scores, and an exceptional young researcher with an h-index of 10 or 15 might conceivably still be working on a post doctorate.