Different tools and measures can be used to measure impact. It is important to understand the difference between the types of impact measures and apply them appropriately.
Measures of Author Impact
h-index Proposed by J.E. Hirsch in 2005, this metric has become one of the most used metrics for measuring a researcher's impact. However, it is much criticized, and often controversial. The h-index is a measure of a researcher's impact that is defined as:
A scientist with an index of h has published h papers each of which has been cited in other papers at least h times.
In response to the need to facilitate comparisons between researchers with different lengths of careers, the m-index or m-quotient, tries to account for the fact that junior researchers have not had time to accumulate citations on their papers. The m-index is:
the h-index divided by the number of years a researcher has been active (measured as the number of years since the first published paper).
In response to criticism that the h-index ignores the number of citations to each article beyond what is needed to achieve a certain h-index, the g-index was proposed by Leo Egghe in 2006 to give more weight to highly-cited articles. The g-index is defined as:
Given a set of articles ranked in decreasing order of the number of citations that they received, the g-index is the (unique) largest number such that the top g articles received (together) at least g2 citations.
A field-normalized indicator of influence, used by the NIH for evaluating the relative merits of biomedical research articles.
The RCR is calculated by dividing the number of citations a paper received by the average number of citations an article usually receives in that field. That number is then benchmarked against the median RCR for all NIH-funded papers.
Use the iCite tool to find the RCR for articles published between 1995 and 2016
A free metric available in Scopus as well as at the SJR site. Includes the journals developed from information contained in the Scopus database.
It is a measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from.