The h-index is a metric for the cumulative impact and productivity of a researcher's scholarly output. If Dr Amit has published 10 research papers that have been cited as follows : 9, 7, 3, 11, 4, 8, 2, 12, 6 and 1, then what is the h-index of Dr Amit ?

Sorting the ten citation counts in descending order gives six papers each cited at least six times, so the h-index is six.

The seventh paper drops to four citations, below seven, ruling out an h-index of seven.

An h-index of five understates the record because a sixth paper still clears the six-citation threshold.

The value four ignores the several papers cited well above four times.

The h-index rewards a sustained body of moderately cited work over one or two highly cited papers.

The i10-index, used by Google Scholar, counts papers with at least ten citations each.