手法を比較

	Scopusデータベース	オープンアクセスジャーナルディレクトリ	h-index（エイチインデックス）
分野	計量書誌学	計量書誌学	計量書誌学
系統	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	2004	2003	2005
提唱者	Elsevier	DOAJ Community (Swedish library consortium, later expanded to international consortium)	Jorge Hirsch, University of California San Diego
種類	Database	Database	Metric
原典	Elsevier. (2024). Scopus: The largest abstract and citation database of peer-reviewed literature. Retrieved from https://www.elsevier.com/products/scopus	Directory of Open Access Journals. (2024). About DOAJ. Retrieved from https://doaj.org/	Hirsch, J. E. (2005). An index to quantify an individual's scientific research output. Proceedings of the National Academy of Sciences USA, 102(46), 16569-16572.
別名	Scopus, Elsevier Scopus	DOAJ, Directory of Open Access	Hirsch index, h factor, h-number
関連	5	5	5
概要	Scopus, owned by Elsevier, is the world's largest abstract and citation database covering peer-reviewed journals, conference proceedings, and book chapters across all scientific disciplines. Launched in 2004, Scopus now indexes over 37 million documents from more than 6,500 journals, with expanded coverage of open-access publications and emerging regional journals. Scopus provides researchers and institutions with comprehensive citation tracking, field-normalized impact metrics (CiteScore, SJR, SNIP), and analytical tools for literature discovery, research evaluation, and institutional benchmarking.	The Directory of Open Access Journals (DOAJ) is a community-maintained, freely accessible directory of high-quality, peer-reviewed open-access journals and articles established in 2003. DOAJ indexes over 20,000 open-access journals across all disciplines (sciences, social sciences, humanities, arts) from diverse geographic regions. The directory serves researchers, librarians, and administrators as the authoritative curated list of legitimate open-access journals—differentiating quality open-access publications from predatory journals that lack genuine peer review. DOAJ quality seal, awarded to journals meeting stricter governance and transparency criteria, enables identification of the highest-caliber open-access publications.	The h-index, or Hirsch index, is a quantitative metric proposed by physicist Jorge Hirsch in 2005 to measure researcher productivity and citation impact simultaneously. A researcher has an h-index of h if they have published at least h papers, each cited at least h times. For example, an h-index of 20 means the researcher has 20 papers each cited at least 20 times. The h-index is widely used in research evaluation, hiring, and promotion decisions, though experts debate its limitations. It provides a single number balancing quantity of publications against quality of citations, offering an intuitive summary of research career impact.