The founding director of CWTS, Ton van Raan, reflects on the origins of the institute:

The Centre for Science and Technology Studies (CWTS) at Leiden University is a renowned research institute focused on the quantitative and qualitative study of science and technology. The Leiden science studies began in 1980 with a small research group and on that basis CWTS was founded in 1986 (first called Science Studies Unit, from 1989 renamed as Centre for Science and Technology Studies). From the start its focus was on bibliometric research and the development of methods to measure scientific output and impact, with a strong emphasis on citation analysis. The basis for this was very practical: the Leiden University Executive Board had decided that the allocation of government funding to departments should be based, next to student numbers, on the proven quality of the research in the departments. For that time, this was quite a revolutionary step. Soon CWTS became a pioneering and global leader in bibliometric studies, significantly contributing to the development of key methodologies for analyzing research performance and mapping of scientific fields. CWTS published the first Handbook of Quantitative Studies of Science and Technology (1988) and organized in Leiden the first international conference specifically devoted to science and technology indicators (STI). From that time, this STI conference has been organized every two years, and since recently every year.

CWTS gained recognition for advancing field-normalized citation impact metrics in order to create robust indicators that account for differences in research fields. At the same time, CWTS developed science mapping on the basis of co-citation and co-word structures. This recognition resulted in an extensive contract-research program that made financing for PhD studies possible. Especially the publishing company Elsevier was particularly generous in the allocation of contract research. From the perspective of institutional academic status the establishment of a professorial chair of quantitative studies of science, probably the first chair in this field worldwide, was crucial. Due to the steady increase of contract work it was decided in 2002 to set up CWTS BV as a spin-off, university-owned company of CWTS. In 2007, CWTS launched the Leiden Ranking (after its predecessor made for the EU in 2001), an influential tool for assessing the research performance of universities worldwide. The Leiden Ranking is unique because it is completely bibliometric, it emphasizes transparency and the use of robust, field-normalized bibliometric indicators.

Over time, CWTS broadened its scope to include innovation studies, science policy issues, and qualitative approaches addressing broader societal issues related to research evaluation. CWTS developed tools like VOSviewer for visualizing different types of bibliometric networks, which has become widely used by researchers. The institute collaborates with governments, funding agencies, and institutions worldwide to provide expertise in research evaluation. CWTS remains at the forefront of bibliometric and research evaluation studies, and is strongly committed to open science practices. It emphasizes responsible metrics, in particular fair and meaningful evaluation practices that minimize biases. CWTS has maintained its reputation as a thought leader in bibliometrics and continues to influence science policy and research evaluation globally.

More information on the origins of CWTS can be found in the Handbook of Bibliometrics.