The History of ISI and the work of Eugene Garfield


Eugene Garfield and his Institute for Scientific Information (ISI)™ pioneered new methods for indexing and disseminating the world’s scientific and scholarly research literature in the second half of the 20th century.

Today, as the research arm of Clarivate™, ISI continues Garfield’s commitment to provide researchers with high-quality data, advanced tools and key insights to accelerate discovery and innovation.

Building a foundation for information science

Garfield introduced the concept of citation indexing for the sciences in 1955 and ISI produced the first Science Citation Index (SCI)™ in 1964. Citation indexing revolutionized information retrieval. By recording and linking the cited references that authors attached to their papers, the SCI represented an “association of ideas index.”

It was an idea before its time, proving Garfield a visionary as well as an innovator. By organizing information through a network of citation connections, Garfield anticipated web hyperlinking and the Google Search algorithm by three decades.

From its foundation in 1960, ISI introduced a range of current awareness and information retrieval products and services covering the literature of the sciences, social sciences and humanities.

A Social Sciences Citation Index (SSCI)™ was introduced in 1973 and an Arts & Humanities Citation Index (AHCI)™ in 1978. Several products focused on the chemical sciences, such as Index Chemicus, the ISI’s first offering in 1960.

The Journal Citation Reports™, introduced in 1976, collated journal-to-journal citations to help librarians and publishers understand the communication system of the science and social sciences literature, as well as the influence and prestige of specific titles. Among other indicators in the product, the most popular was the Journal Impact Factor™.

Other ISI products were designed to keep researchers up to date on new publications in their fields, such as Current Contents, a weekly bulletin presenting the content pages of journals, eventually issued in seven field-specific editions.

SCI data also served as a foundation for quantitative studies in the history and sociology of science and eventually gave birth to the field of scientometrics.

Carrying the torch of Garfield’s intellectual legacy

In 1992, the Thomson Corporation acquired ISI. Thomson merged with Reuters in 2008 to form Thomson Reuters. In 2016, the scientific and scholarly information business of Thomson Reuters, including the products and services of the former ISI, was spun out to private ownership and rebranded as Clarivate.

ISI was revived as a research division within Clarivate in 2018 to conduct scientometric research, to advise the company on the content and features of its products, and to offer guidance to the research community on best practices in the use of quantitative indicators in the evaluation of research. It also maintains the foundational knowledge and editorial rigor upon which the Web of Science index and its related products and services are built.

ISI’s reports and publications and participation in events and conferences play a crucial role in extending and improving the knowledge base that is essential to our colleagues, partners and all those who deal with research in academia, government organizations, corporations, as well as funders and publishers.

Timeline of key events:

  • 1960: Eugene Garfield establishes the Institute for Scientific Information (ISI) in Philadelphia, Pennsylvania
  • 1964: ISI publishes the first Science Citation Index (SCI), fulfilling Garfield’s 1955 proposal for citation indexing of the scientific literature
  • 1973: The U.S. National Science Foundation incorporates SCI publication and citation data in the first Science Indicators report on national performance in research
  • 1973 / 1978: ISI expands coverage of the scholarly literature with the introduction of the Social Sciences Citation Index (SSCI) and the Arts & Humanities Citation Index (AHCI), respectively
  • 1976: ISI publishes the first Journal Citation Reports, including Journal Impact Factors and other descriptive statistics
  • 1979: Garfield publishes Citation Indexing – Its Theory and Application in Science, Technology, and Humanities
  • 1981: The ISI Atlas of Science is published, based on research by ISI’s Chief Scientist Henry Small and using co-citation to map research topics
  • 1988: ISI introduces the Science Citation Index on CD-ROM
  • 1992: The Thomson Corporation acquires ISI
  • 1997: The Web of Science first launches online, bringing together the SCI, SSCI and AHCI
  • 2001: Essential Science Indicators is introduced – a web-based analytic tool providing data on the output and impact of researchers, institutions, nations and journals, as well as highly cited papers and research fronts
  • 2009: InCites, a platform for in-depth analysis of research performance integrated with complete Web of Science data, is launched
  • 2016: Clarivate acquires the ISI product range from Thomson Reuters Corporation
  • 2017: The life of Eugene Garfield (1925-2017) is commemorated and celebrated September 15-16 in Philadelphia, Pennsylvania
  • 2018: ISI formally re-established within Clarivate, continuing Garfield’s original business and intellectual legacy


Links of interest

A wealth of information on the history of ISI can be found on Garfield’s personal web pages, maintained at the University of Pennsylvania, including:

Current Contents Essays

Garfield’s 15–volume collection of Current Contents essays and other writings (Essays of an Information Scientist).

Samuel Lazerow, “Institute for Scientific Information” (1974)



The who and why of ISI (1975)



Origins of Current Contents, ISI, and computer-Aided information retrieval.



Tony Cawkell and Eugene Garfield, “Institute for Scientific Information” (2001)



60 Years of Invention and Innovation

Grimwade A. Eugene Garfield – 60 Years of Invention and Innovation. Frontiers in Research Metrics and Analytics 3, 14.

The origins and importance of analyzing citation data

Pendlebury D. “The threads that hold the fabric of science together”: The origins and importance of analyzing citation data. Web of Science blog, January 2021.

Eugene Garfield and the Institute for Scientific Information

Pendlebury D. Eugene Garfield and the Institute for Scientific InformationHandbook Bibliometrics, Rafael Ball, ed., Walter de Gruyter, pp 27-40.

Science Watch archives



ISI reports



ISI reports and publications