Below you see the metrics in an example that are available via PoP. Some of the moste common are explained or linked..
ACC = annual citation count (= citations / years_since_publication)
ACCn = number of articles with an annual citation count >= n
The various ACC levels are subsets of each other; all articles in acc10 are also part of acc5, acc2, and acc1; etc.
A scholar has index h if h of his/her Np papers have at least h citations each, and the other (Np-h) papers have no more than h citations each.
An H-index of 45 means that a scholar has published 45 articles, each of these articles have been quoted at least 45 times.
The g-index is an alternative for the older h-index, which doesn’t average the numbers of citations. The h-index only requires a minimum of n citations for the least-cited article in the set and thus ignores the citation count of very highly cited papers The g-index can be seen as the h-index for an averaged citations count.
g-index looks at overall record
A g-index of 20 means that a scholar has published at least 20 articles that combined have received at least 400 citations. However, unlike the h-index these citations could be generated by only a small number of articles. For instance a scholar with 20 papers, 15 of which have no citations with the remaining five having respectively 350, 35, 10, 3 and 2 citations would have a g-index of 20, but a h-index of 3 (three papers with at least 3 citations each).
Roughly, the effect is that h is the number of papers of a quality threshold that rises as h rises; g allows citations from higher-cited papers to be used to bolster lower-cited papers in meeting this threshold. Therefore, in all cases g is at least h, and is in most cases higher. However, unlike the h-index, the g-index saturates whenever the average number of citations for all published papers exceeds the total number of published papers; the way it is defined, the g-index is not adapted to this situation.