CWTS Leiden Ranking (Traditional Edition)
The CWTS Leiden Ranking reports bibliometric indicators for major research universities worldwide, such as publication output (P) and the share of highly cited papers (PP(top 10%)), without collapsing them into one score. Research managers and analysts use it as a transparent, data-only view of research volume, impact and collaboration.
- Reliability
- Grade A · 11/12
- Ranks
- Universities
- Editions
- 15 since 2007
- Method
- Data
- How items get in
- Compiled by the publisher
- Status
- Active
Editions
| Edition | Published | Top of the list | On record |
|---|---|---|---|
| 2025 | October 29, 2025 | Not recorded | At the publisher |
| 2024 | 2024 | Not recorded | At the publisher |
| 2023 | 2023 | Not recorded | At the publisher |
| 2022 | 2022 | Not recorded | At the publisher |
| 2021 | 2021 | Not recorded | At the publisher |
| 2020 | 2020 | Not recorded | At the publisher |
| 2019 | 2019 | Not recorded | At the publisher |
| 2018 | 2018 | Not recorded | At the publisher |
| 2017 | 2017 | Not recorded | At the publisher |
| 2016 | 2016 | Not recorded | At the publisher |
| 2015 | 2015 | Not recorded | At the publisher |
| 2014 | 2014 | Not recorded | At the publisher |
| 2013 | 2013 | Not recorded | At the publisher |
| 2011/2012 | 2012 | Not recorded | At the publisher |
| 2007 | 2007 | Not recorded | At the publisher |
How the ranking works
The Traditional Edition uses Web of Science core publications (Science Citation Index Expanded, Social Sciences Citation Index, Arts and Humanities Citation Index) over four-year windows (2020 to 2023 in the 2025 edition, with citations through 2024). Indicators cover output (P), scientific impact (P(top 10%), PP(top 10%) and similar, normalized by field and year), collaboration, open access and gender. Impact indicators use fractional counting by default, and users can sort by any indicator; there is no composite score. Universities need a minimum number of publications to be included.
Scores only: Indicator scores are published without a single overall rank. No application or fee; universities are included automatically once they pass a minimum publication threshold in Web of Science.
How far to trust it
Superscout grades every ranking on six criteria, each scored 0 to 2. CWTS Leiden Ranking (Traditional Edition) scores 11 of 12, grade A.
- Transparency 2/2
- Indicators, counting methods and data files are public.
- Independence 2/2
- Academic producer; inclusion is automatic and free.
- Evidence 2/2
- Built entirely from publication and citation data.
- Stability 2/2
- Indicator framework consistent across editions; coverage grows gradually.
- Coverage 1/2
- About 1,600 universities that pass a publication threshold.
- Track record 2/2
- Published since 2007.
History
CWTS at Leiden University launched the ranking in 2007 (Wikipedia). Data files are published for 2011/2012 and every edition from 2013 to 2025, and coverage grew from 750 universities in 2014 to 1,594 in 2025. In 2024 CWTS launched an Open Edition based on OpenAlex data; the Web of Science version has since been labeled the Traditional Edition, and both are scheduled for Nov. 4, 2026 releases.
How it is received
The Leiden Ranking is respected among bibliometricians for its transparency and its refusal to publish a composite score, and CWTS publishes responsible-use principles. Loet Leydesdorff criticized its field normalization at category level for giving more weight to older publications, reviews and high-citation fields (per Wikipedia). Wikipedia also notes UK universities score lower here than in reputation-based rankings such as THE or QS.
Strengths
- Purely bibliometric, with no reputation surveys.
- Offers size-dependent and size-independent indicators instead of a single composite.
- Stability intervals and responsible-use guidance are published.
- Free, with downloadable data for every edition since 2011/2012.
Weaknesses
- No single ranking, which makes headline comparisons harder.
- Covers research publications only; no teaching, patents or startup outcomes.
- Field coverage depends on the underlying database (Web of Science or OpenAlex).
- Selection threshold excludes smaller institutions.
Open questions
Facts not verified yet. They stay visible so they are not mistaken for settled facts.
- The brief says the Traditional Edition ends after its Nov. 2026 update; no such notice was found on the CWTS pages accessed (the site only announces the Nov. 4, 2026 release).
- Editions between 2007 and 2011 (for example 2008 and 2010) not verified.
- Exact release dates for 2013 to 2024 not confirmed.
- No entries transcribed: tables render client-side and data sit in Excel/ZIP files.
- Which edition Wikipedia's '19 of the top 25, led by Zhejiang' statement refers to, and by which indicator, is not confirmed.
Superscout describes CWTS Leiden Ranking (Traditional Edition) independently from the publisher’s own pages and outside coverage, linked below. The rankings belong to Centre for Science and Technology Studies (CWTS), Leiden University.