Hirsch index (H-Index)

J. E Hirsch (2005), a professor of physics at the University of California, introduced a new index known as “Hirsch Index” (H-index) for evaluation and measurement of the scientific output of researchers in an article with the title of “an index for assessing the research output of researchers individually”.

The H-index answers the question of: What role does each researcher play independently in promoting and extending the boundaries of science in different fields of human knowledge?

H-index of a researcher includes H number of his papers, each of which has been cited H times. In other words, if an author has six articles and each paper has been cited at least six times, the H-index of that researcher is six. However, if the number of articles of the same person is more than six and the citation number of the papers is below six, it would not affect his H-index. Obviously, the larger the H-index, the higher the scientific power and impact of the researcher on science. This index scores the result of the work of the researcher using the number of citations.

To obtain the H number after the search, the articles must be sorted by citation in descending order, and the article number (article rank) must be compared with the number of citations so that the number of citations would be equal to or less than the article rank. We draw a credit boundary line known as “green horizontal line” above the first paper that has a citation value below its rank. The number of articles above this line, or in other words, the rank of the last article above the line, forms the value of H-index, which means that the number of citations to these articles is equal or more than the value of H-index.