The G-index was proposed by Leo Egghe in his paper "Theory and Practice of the G-Index" in 2006 as an improvement on the H-Index.
G-Index is calculated this way: "[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 g^2 citations." (from Harzig's Publish or Perish Manual)
Advantages of the G-Index:
Disadvantages of the G-Index: