h-index
The h-index is an author-level metric that measures both the productivity and citation impact of the publications, initially used for an individual scientist or scholar.
The h-index correlates with success indicators such as winning the Nobel Prize, being accepted for research fellowships and holding positions at top universities.
The index has more recently been applied to the productivity and impact of a scholarly journal[2] as well as a group of scientists, such as a department or university or country.
Hirsch has demonstrated that h has high predictive value for whether a scientist has won honors like National Academy membership or the Nobel Prize.
[14] For example, the Meho and Yang study found that Google Scholar identified 53% more citations than Web of Science and Scopus combined, but noted that because most of the additional citations reported by Google Scholar were from low-impact journals or conference proceedings, they did not significantly alter the relative ranking of the individuals.
[16] Hirsch suggested that, for physicists, a value for h of about 12 might be typical for advancement to tenure (associate professor) at major [US] research universities.
A value of about 18 could mean a full professorship, 15–20 could mean a fellowship in the American Physical Society, and 45 or higher could mean membership in the United States National Academy of Sciences.
[4] For the most highly cited scientists in the period 1983–2002, Hirsch identified the top 10 in the life sciences (in order of decreasing h): Solomon H. Snyder, h = 191; David Baltimore, h = 160; Robert C. Gallo, h = 154; Pierre Chambon, h = 153; Bert Vogelstein, h = 151; Salvador Moncada, h = 143; Charles A. Dinarello, h = 138; Tadamitsu Kishimoto, h = 134; Ronald M. Evans, h = 127; and Ralph L. Brinster, h = 126.
[18] The threshold for space science is the highest (2236 citations), and physics is followed by clinical medicine (1390) and molecular biology & genetics (1229).
The h-indices for ("full") professors, based on Google Scholar data ranged from 2.8 (in law), through 3.4 (in political science), 3.7 (in sociology), 6.5 (in geography) and 7.6 (in economics).
[27] The h-index does not provide a significantly more accurate measure of impact than the total number of citations for a given scholar.
, where N is the total number of citations, which, for mathematics members of the National Academy of Sciences, turns out to provide an accurate (with errors typically within 10–20 percent) approximation of h-index in most cases.
[29][30] The h-index can be manipulated through self-citations,[31][32][33][34] and if based on Google Scholar output, then even computer-generated documents can be used for that purpose, e.g. using SCIgen.
Recent research shows clearly that the correlation of the h-index with awards that indicate recognition by the scientific community has substantially declined.
When compared with a video creator's total view count, the h-index and g-index better capture both productivity and impact in a single metric.
