Basically it is the number N of your publications that have N or more citations. So if you were to rank all of your publications in terms of references, the top one (i=1) having the most and the bottom one (i=Max) having the least, then your h-index is just above the publication in which: references < i.
The h-index was suggested in 2005 by Professor Hirsch to quantify a scientist's publication productivity. Hirsch defines it as follows: "A scientist 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."
Within the scientific community, h-index is considered to be a very important parameter in the evaluation of the impact of the work of a researcher. Indeed, it is related to citations so (theoretically) the higher the quality of the work the higher the h-index. However, in general this is not always true and some situations show that h-index can provide misleading information about the quality of a scientist's output (e.g. citations made in a negative context or citations made to fraudulent or retracted works).
If you want to have a particularly high h-index, you should join a really large collaboration that works on something that many people in your field think is very important. Many collaborators will help you get many papers - and other people thinking this is important will get these papers many citations. This shows that the h-index is (like other measures, e.g. the RG score...) insufficient to rate a scientist's abilities. I know doctoral students that had at their graduation an h-index of 40+, and tenured professors who had
According to Google citation calculation, h-index is the largest number h such that h publications have at least h citations. Joachim's point is that If you want to increase h value, join a group that has increased number of publications while slef citing the previous articles.
Not so long before, 'total impact factor (IF) is the issue, and now h-index is the important benchmark among researchers. More or less, previous question as 'what is the level of a researcher's published work?'; for h-index as 'how popular is the researcher?'. Even though that's not always true as an evaluation point, it is unavoidable. I think Joachim has good point of view,..if publish to communicate your research and enjoy doing your research... ..truely.
h-index*: h is the number of articles greater than h that have at least h citations. For example, an h-index of 20 means that there are 20 items that have 20 citations or more.