Najko Jahn
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najko.bsky.social
Najko Jahn
@najko.bsky.social
230 followers 1K following 26 posts
Data Analyst Scholarly Communications at State and University Library Göttingen , #scholcomm #rstats #bibliometrics #openaccess #openscience #lagotto
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najko.bsky.social
Just out: Open metadata enable large-scale hybrid open access studies. Cross-database comparison using major bibliometric databases shows that transformative agreements have been the main driver of open access. But paywalls still dominate.

doi.org/10.1007/s111...
Comparison of hybrid journal indexing by data source, 2019–2023. Only hybrid journals present in the cOAlition S Transformative Agreement Data dump with at least one open access article are considered. A presents the number of journals, B the number of articles (DOI), distinguishing between shared DOI corpus and surplus in hoaddata. Box plots C shows the 5-years journal article volume (log scale). Note that intersections sets with at least 30 journals are shown Development of open access in hybrid journals in transformative agreements by data source and author role, 2019–2023. Figure shows the open access percentage (A), the number (B) and the percentage (C) of open access articles enabled by transformative agreements.
August 11, 2025 at 9:46 AM
najko.bsky.social
Just an (late) update. Added posted-content to our public scholarly data warehouse using the May 2025 Crossref dump (following @mfenner.bsky.social advise).
subugoe.github.io/scholcomm_an...

Managed to pull together the data in 5 secs, CSV available here: drive.google.com/file/d/1s1cP...
SQL query used to obtain publication and DOI deposition dates for preprints using Crossref metadata, as provided by the SUB Göttingen open scholarly data warehouse.
June 16, 2025 at 3:18 PM
najko.bsky.social
Includes open data on transformative agreements

- 1,043 TAs with 17,199 journals and 5,355 institutions
- 1,362,221 eligible articles

Preserved and curated from various sources, e.g. #esac, @coalitions-oa.bsky.social & #OpenAlex

Overview and first steps: github.com/kbopenbib/kb...
May 5, 2025 at 12:38 PM
najko.bsky.social
Endlich Mai und Softeis
Lagotto Alfons with ice cream Lagotto jumping
May 1, 2025 at 5:58 PM
najko.bsky.social
Just out: Analysis of hybrid #openaccess through transformative agreements, comparing open metadata (hoaddata, from #coalitionS, #Crossref & #OpenAlex) with Scopus & Web of Science. Open metadata performs well, with correlations but surprising differences in OA evidence.

arxiv.org/abs/2504.15038
Development of open access in hybrid journals in transformative agreements by data source and author role, 2019-2023. Figure shows the open access percentage (A), the number (B) and the percentage (C) of open access articles enabled by transformative agreements. Development of open access in hybrid journals included in transformative agreements by data source, author role and publisher, 2019-2023. Figure shows the open access percentage (A), the number (B) and the percentage (C) of open access articles enabled by transformative agreements. Comparison of hybrid open access by country, 2019-2023. Scatterplots distinguish between proprietary databases Scopus and Web of Science, and author role. The x-axis shows hoaddata indicators. A) Five-years article volume, B) open access percentage in hybrid journals, (A and B limited to countries with > 10.000 articles published), C) number and D) percentage of open access articles enabled by transformative agreements (limited to countries with > 1.000 open access articles enabled by transformative agreements). Line represents line of equality. Comparison of hybrid journal indexing by data source, 2019-2023. Only hybrid journals present in the cOAlition S Transformative Agreement Data dump with at least one open access article are considered. A) presents the number of journals, B) the number of articles (DOI), distinguishing between shared DOI corpus and surplus in hoaddata. Box plots (C) shows the five-years journal article volume (log-scale)
April 24, 2025 at 2:30 PM
najko.bsky.social
We have noticed a massive decrease in green #openaccess evidence in Scopus in 2024.

subugoe.github.io/scholcomm_an...

Elsevier has now confirmed and fixed the issue. Please note that you may need to rerun your analysis using the updated open access evidence.
January 20, 2025 at 10:54 AM
najko.bsky.social
Letzter Freibadtag des Jahres
October 1, 2023 at 6:04 PM