An h-index measures the broad impact of an individual’s work, and is a method to compare authors within a discipline, especially in the sciences.
Dr. J. E. Hirsch created the h-index in the paper An index to quantify an individual’s scientific research output in 2005.
He asked and answered "How does one quantify the cumulative impact and relevance of an individual’s scientific research output?"
A scientist has index h if h of his or her Np papers have at least h citations each and the other (Np h) papers have h citations each.
Data that is used for citation measurements for the h-index include:
Any database could measure an h-index from its citation data.
Currently, Web of Science and Scopus (look in Author Details) display it.
If your h-index score is 241, that means you have at least 241 papers/articles that have been cited by at least 241 other papers/articles.
Congratulations! That is a high h-index score.
Calculate your h-index using Google Scholar 'Cited by' data.