H-Index – an H-Index can be applied either at the author-level or at the journal level. It was developed by Jorge Hirsch in 2005 to capture both productivity (number of publications) and impact (number of citations). H-Index is calculated by the highest number of articles that have that same number of citations. So an author or journal with an h-index of 25 has at least 25 papers that have been cited at least 25 times. H-Index is the standard metric in most cases.1
H5-Index – an H5-Index is most commonly used at the journal level. It attempts to capture a better picture of impact by giving the average h-index of the most recent.5
G-Index – the G-Index was developed in 2006 as an attempt to improve upon the H-Index. The intention behind the G-Index is to weigh more heavily on the impact of individual articles rather than on an author’s overall productivity. An author with a 5 G-Index has 5 (g) papers that have been cited at least 25 (g2) times.2
