Ludo Waltman

@ludowaltman.bsky.social

Scientific Director Centre for Science and Technology Studies (CWTS), Leiden University; Open Science Ambassador Leiden University; Co-chair Research on Research Institute (RoRI); President ASAPbio; Editor-in-Chief MetaROR (MetaResearch Open Review)

@pkp.sfu.caReposted by @ludowaltman.bsky.social

💡 Open peer review in OJS 3.6: call for editors to express interest in taking part in a study

PKP and #ScholCommLab are working together on a study and we want to know if you are interested in taking part.

No need to commit just yet but you can express your interest at pkp.sfu.ca/2026/10/05/c...

@prcalliance.bsky.socialReposted by @ludowaltman.bsky.social

Join us for the “Publish, Review, Curate (PRC): Shaping the future of scholarly publishing” launch event, where Ludo Waltman @ludowaltman.bsky.social, Scientific Director, Center for Science and Technology Studies (CWTS) at Leiden University, will give a keynote talk.

@cwts.nlReposted by @ludowaltman.bsky.social

📣 New research seminar!

This Friday, @roderikrekker.bsky.social will give a presentation on the politicization of public trust in science, its causes, consequences, and cures.

🎧 Make sure to join!

📅 Friday, 9/10/2026 | 3:00-4:15 PM (CEST)
📌 Online

More information on our website 👉 edu.nl/rf3jj

@metaror.bsky.socialReposted by @ludowaltman.bsky.social

You might be aware that Crossref records can contain funding metadata. But how complete is their coverage? According to this new paper, an approximate 30% of funding acknowledgments do not get deposited in Crossref.

👇 Read the evaluation now on MetaROR: metaror.org/article/lost...

@msphelps.bsky.socialReposted by @ludowaltman.bsky.social

Very pleased with this milestone - 150+ signatory organizations have signed the Barcelona Declaration on Open Research Information!

@metaror.bsky.socialReposted by @ludowaltman.bsky.social

This new MetaROR-evaluated paper introduces "the innovation annulus: the zone between freely available structured data and the advancing frontier of commercially refined knowledge products," which is "a permanent, functional feature of the ecosystem -- not a pathology to eliminate." 👇 Read now

@metaror.bsky.socialReposted by @ludowaltman.bsky.social

This new study takes a meta-perspective on reproducibility by examining replication projects themselves. The reviewers agree the manuscript addresses an important and worthwhile question but identify fundamental problems that currently prevent confidence in the study results. 👉 Read now on MetaROR

@metaror.bsky.socialReposted by @ludowaltman.bsky.social

How sustainable are the databases that life sciences researchers depend on? This new study examined 9 of them to find out. Both reviewers find the study timely and valuable. One reviewer suggests another level of synthesis in the thematic analysis would be helpful. 👉 Read now on MetaROR

@metaror.bsky.socialReposted by @ludowaltman.bsky.social

This article by Yu Zhu and Jiyuan Ye presents a theoretical framework for research evaluation developed in China, highlighting the current binary opposition between qualitative & quantitative methods in evaluation practices. 👉 Read the assessment, reviews, author response & full article on MetaROR

@prcalliance.bsky.socialReposted by @ludowaltman.bsky.social

"PRC makes the full process of scientific dispute visible: instead of concealing deliberation behind editorial decisions, it exposes disagreement, revision, and assessment as integral parts of scientific discovery."

@asapbio.bsky.socialReposted by @ludowaltman.bsky.social

Research assessment and scholarly publishing are two sides of the same coin, and achieving meaningful progress in both requires coordination between the reform movements. 🧵

@prcalliance.bsky.socialReposted by @ludowaltman.bsky.social

✨Keynote talk by @ludowaltman.bsky.social, Scientific Director, CWTS at Leiden University, ✨Contributions from PRC implementers representing the platforms and services that make PRC a reality ✨A researcher panel discussion about their experiences publishing using the PRC model

@dsquintana.bsky.socialReposted by @ludowaltman.bsky.social

New preprint! 🎉 I analysed 1660 papers from 4 psychology journals and found materials sharing went from 9% of papers in 2015 to 82% in 2025, and these materials *do* get downloaded — a median of 135 times each. BUT shared code is often hard to run. doi.org/10.31234/osf...

Let's walk through it 🧵

Two-panel figure. Panel a is a flow diagram tracking 1,611 empirical psychology articles from publication year (545 in 2015, 552 in 2020, 514 in 2025) to repository-link type: 785 link an OSF project, 85 link another platform, and 741 link no repository. Of those with an OSF link, download counts were retrieved for 670 and not retrieved for 115. Panel b is a line chart of the share of empirical papers linking OSF across 2015, 2020 and 2025. The overall rate, shown as a dashed black line, rises from 9% to 57% to 82%. All four journals rise steeply and end close together: Psychological Science 92%, JESP 89%, JML 83%, Cognition 76%, with Psychological Science highest throughout.Three-panel figure. Panel a: ridgeline plot of downloads per file by material type on a log scale, with the percentage never downloaded labelled for each — archive 16% of 545 files, documents 20% of 2,970, code 12% of 3,471, other 17% of 1,646, data 21% of 10,051, media 35% of 2,120, images 35% of 4,102. Most files cluster between 1 and 10 downloads, with long right tails past 100. Panel b: ridgeline plot of downloads per paper by journal, log scale, with dashed median lines; Psychological Science is highest, then JESP, JML and Cognition. Panel c: stacked bars showing, for documents, data and code separately, the share of papers by download band (0, 1–10, 11–100, more than 100) in 2015, 2020 and 2025. The share exceeding 100 downloads falls sharply over time in all three types, from roughly two-thirds in 2015 to a quarter or less in 2025, as the 1–10 band grows.Four-panel figure. Panel a: statistical languages detected among 333 papers with retrievable code — R 88%, SPSS 12%, Stata 4%, SAS 1%. Panel b: code red flags among those 333 papers — 34% hard-code an absolute path, 40% reference a missing file — above documentation among 672 OSF-linked papers — 21% have a README, 30% are documented by README, description or wiki. Panel c: among 562 Elsevier papers with no repository link, 44% (245) host at least one journal supplementary file but only 14% (77) host data, code or an archive. Panel d: composition of those 448 hosted files — documents 52%, data 21%, media 9%, other 7%, archive 6%, code 3%, images 1%. The code panels are green, the journal-supplement panels blue.Coefficient plot (download predictors) Dot-and-whisker plot of three standardised predictors of OSF download volume, each with a 95% confidence interval. Repository size (number of files) has the largest effect at about 0.76, citations about 0.38, and altmetric attention about 0.12. All three intervals sit entirely above zero, so each predicts more downloads, with repository size roughly twice the effect of citations and six times that of attention. X-axis: standardised effect, −0.2 to 1.0.
@jeroenbosman.bsky.socialReposted by @ludowaltman.bsky.social

On 20260917 @utrechtuniversity.bsky.social Utrecht University published its new Open Access policy 2026-2030: doi.org/10.5281/zeno.... It widens and deepens the scope, with all publication types in scope and addressing topics like knowledge equity and governance & ownership.

Screenshot from cover of the new Utrecht University Open Access Policy 2026-2030, with the university logo, the title and an orange open access icon on top of an arrow pointing from 2026 to 2030.
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