Average H-Index depends on collection policy of the source​

Value for the H-index depends on source’s content and coverage.

WOS

  • Citation data only for the records indexed by database.

  • Limited number of journals.

  • European bias.

  • Calculates the H-index of an author from 1965 – current.

  • Limited number of journals in non-English languages.

  • Clear results from scholarly journals.

  • "In press" articles are not indexed because of editorial policy.

    • Only in their final form.

  • Self-citations exclusion option.

  • Access via subscription.

SCOPUS

  • Citation data only for the records indexed by database.

  • More content (about 20,000 journals) than in WOS (about 12,000 journals).

  • American bias.

  • Calculates the H-index of an author from 1996 – current.

  • Limited number of journals in non-English languages.

  • Clear results from scholarly journals.

  • One version of a paper in results.

  • "In press" articles are included.

  • Self-citations exclusion option.

  • Access via subscription.

GOOGLE SCHOLAR

  • Scholar’s work may be published in journals not covered by WOS and Scopus.

  • Larger number of journals than in WOS and Scopus *not all scholarly journals are indexed in Google Scholar.

  • Larger number of publications in non-English languages than in WOS and Scopus.

  • Affection on value of H-index of additional irrelevant citations results from nonscholarly citations (records from unknown sources and informal material).

    • Not all of them are of the same quality as those found in the Web of Science or Scopus.

  • In some cases Scholar indexes preprint and journal version of a paper and provides in the results the sum of the two counts, so citations are spread over the duplicates.

  • Provides an H-index only for researchers who created a user profile for themselves.

  • Counts self-citations.

  • Freely accessibly from the internet.

PUBLISH OR PERISH

  • Publish or Perish uses Google Scholar data to calculate H-index (provides results from 1000 papers maximum).

  • Publish or Perish use the Advanced Scholar Search capabilities and because of this fact the results are not always 100% accurate.

  • Software may be download from the Publish or Perish website.

  • There are works in the list that are not by the author you are assessing.

    • It is possible to go through the list and deselect any works by the wrong author.

  • Merges duplicate records.

CITESEERX

  • CiteSeerX focuses primarily on the literature in computer and information science.

  • Uses ACI (Autonomous citation indexing) to automatically extract citations and create a citation index.

  • Computes citation statistics and related documents for all articles cited in the database, not just the indexed articles.

The optimal methodology

The optimal methodology to value H-index for researcher is to consult Google Scholar in addition to Web of Science or Scopus.