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František Bartoš

@fbartos.bsky.social
923 followers 206 following 135 posts

PhD Candidate | Psychological Methods | UvA Amsterdam | interested in statistics, meta-analysis, and publication bias | once flipped a coin too many times

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Reposted by František Bartoš
Matthew B. Jané @matthewbjane.bsky.social · 13/09/2026
I’ve been quiet on social media lately, but today I’m launching Audit Clinical Evidence (ACE), an initiative I’ve been developing over the past year. Take a look: AuditClinicalEvidence.org
auditclinicalevidence.org
ACE
Independent audits of published clinical research for statistical errors, data inconsistencies, and research integrity violations.
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František Bartoš @fbartos.bsky.social · 04/09/2026
yeah, I given up on commenting on these small details at this points lol
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František Bartoš @fbartos.bsky.social · 04/09/2026
I guess they meant "asymmetrical" instead of "a symmetrical"
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František Bartoš @fbartos.bsky.social · 04/09/2026
Xu, T., & Wang, H. (2024). The effectiveness of artificial intelligence on English language learning achievement. System, 125, 103428. doi.org/10.1016/j.sy...
doi.org
Redirecting
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František Bartoš @fbartos.bsky.social · 04/09/2026
And another one: > As Fig. 2 indicates, the funnel plot had a symmetrical distribution, indicating no publication bias in this meta-analysis. Besides, the results of the classic fail-safe N ... reveals that 6619 missing studies would be needed to nullify the effect size ...
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František Bartoš @fbartos.bsky.social · 04/09/2026
Huang, X., Xu, W., Li, F., & Yu, Z. (2024). A meta-analysis of effects of automated writing evaluation on anxiety, motivation, and second language writing skills. The Asia-Pacific Education Researcher, 33(4), 957-976. link.springer.com/article/10.1...
link.springer.com
A Meta-analysis of Effects of Automated Writing Evaluation on Anxiety, Motivation, and Second Language Writing Skills - The Asia-Pacific Education Researcher
With the rapid advancement of information technologies, automated writing evaluation technologies have developed so fast that they can be applied to writing assessments. However, scanty studies have p...
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František Bartoš @fbartos.bsky.social · 04/09/2026
Another meta-analyses on AI in education. > Fig. 2 provides a visual representation of the distribution of effect sizes, indicating that the effect sizes are nearly symmetrically distributed... This distribution suggests that there is no evidence of publication bias present...
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Reposted by František Bartoš
Beth Clarke @bethclarke.bsky.social · 21/08/2026
I’m hiring a PhD student to work with me on metascience in psychology at @zpid.bsky.social! The position is very open - could cover a wide range of topics/themes 🤸🏻‍♀️✨ If you have questions, please reach out! Applications are open until October 1st. leibniz-psychology.onlyfy.jobs/en/job/fyjwt...
leibniz-psychology.onlyfy.jobs
PhD in Psychological Meta-Science (m/f/d)
Become part of the open science movement The Leibniz Institute for Psychology Information (ZPID) in Trier (Germany) is an internationally recognized research-based psychology service center located in...
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Reposted by František Bartoš
Jin X. Goh | 吴晋勋 @jinxungoh.bsky.social · 11/08/2026
Meme of a young person assisting an old lady. The old person said “I remember when you could store data on osf.” The young person said “sure professor. Let’s get you to bed”
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František Bartoš @fbartos.bsky.social · 11/08/2026
My supervisor vibecoded a nice visualization for the same-side bias in coin flips effect:
bayesianspectacles.org
Coin precession simulation with same-side fraction
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František Bartoš @fbartos.bsky.social · 05/08/2026
For the revision for our "Meta-Analysis with JASP, Part I: Classical Approaches" tutorial, I recorder a series of YouTube videos walking through the examples in JASP www.youtube.com/watch?v=mbou... First time doing this. Do you find walkthroughs like this useful? Let me know any suggestions!
youtube.com
Meta-Analysis with JASP, Part I: Classical Approaches (Example 1)
YouTube video by JASP Statistics
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František Bartoš @fbartos.bsky.social · 21/07/2026
Join the JASP workshops at the last week of August!
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František Bartoš @fbartos.bsky.social · 18/07/2026
- Good Scientific Practices for Sim. Studies - Toward Reporting Standards for Methodological Research - Transparency Over the Life-Cycle of a Sim. Study - Multi-Method Specification Curves for Presenting Sim. Results - Living Synthetic Benchmarks: A Neutral and Cumulative Framework for Sim. Studies
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František Bartoš @fbartos.bsky.social · 18/07/2026
Come to our #IMPS2026 symposium on methodology of simulation studies with Richard Feinberg, @karolinehuth.bsky.social , Mirka Henninger, and David Kronthaler on Tuesdat at 12:45 to room 102. The symposium has the following talks:
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František Bartoš @fbartos.bsky.social · 11/07/2026
New features: - Classical Generalized (GLMM) Meta-Analysis - Effect Size Aggregation - separate Forest Plot builder - Risk of Bias Plot - variable exports for derived fit information in classical analyses (i.e., residuals, predicted values, weights...) - several small updates ...
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František Bartoš @fbartos.bsky.social · 11/07/2026
@jaspstats.bsky.social released a new of the Meta-Analysis module -- if you have the latest version of JASP you should see a small blue download icon next to the Meta-Analysis module on the ribbon. You can update it via the Module Store (see screenshot below).
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František Bartoš @fbartos.bsky.social · 02/07/2026
I was presenting a poster at ISBA overviewing the RoBMA R package for Bayesian meta-analysis. Check it below to see a brief summary of the latest changes with the new 4.0 version and the future directions!
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Reposted by František Bartoš
Prof Andy Field @profandyfield.com · 25/06/2026
Want to learn JASP? My colleagues (@ejwagenmakers.bsky.social) at UVA are running workshops in August: jasp-stats.org/2026/02/03/h...
jasp-stats.org
Hybrid Workshop "Discovering Statistics Using JASP", August 24th, 2026 - JASP - Free and User-Friendly Statistical Software
We are happy to announce that the JASP team will offer a week of workshops in Amsterdam this summer.  In this blogpost we’ll highlight the first of four workshops: “Discovering Statistics Using JASP“....
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Reposted by František Bartoš
Wolfgang Viechtbauer @wviechtb.bsky.social · 22/06/2026
The standard random-effects model in meta-analysis assumes that the amount of heterogeneity is homoscedastic. This assumption may not be true. I derived and examined various tests for heteroscedastic heterogeneity. See osf.io/cavhy for a preprint describing these methods. #MetaAnalysis #RStats
osf.io
OSF
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František Bartoš @fbartos.bsky.social · 18/06/2026
doi.org/10.1016/j.co... doi.org/10.3389/fpsy... doi.org/10.1057/s415...
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František Bartoš @fbartos.bsky.social · 18/06/2026
Out of curiosity I checked a the first author's google scholar. He seemed to have co-authored additional three meta-analyses last year. Two of those show quite unbelievable effect sizes again. (I guess the d = 2.5 is fine when the rest contains d around 4)
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František Bartoš @fbartos.bsky.social · 18/06/2026
Currenly revising our critique of meta-analyses of AI/LLM on learning. Some of the original meta-analyses are beyond ridicolous. This one has 87 citations since published in 2025. (doi.org/10.1177/0266...)
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František Bartoš @fbartos.bsky.social · 03/06/2026
We still have a couple of spots left for JASP workshops August! 24: Discovering Statistics using JASP 25: State-of-the-Art Meta-Analysis using JASP 26: A Crash Course in Machine Learning with JASP 27-28: Theory and Practice of Bayesian Hypothesis Testing with JASP jasp-stats.org/workshops/
jasp-stats.org
Workshops - JASP - Free and User-Friendly Statistical Software
The JASP team is excited to support four workshops this year (2026). Each of these workshops can be attended either in person (at the University of Amsterdam) or online: On Monday August 24th, we orga...
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František Bartoš @fbartos.bsky.social · 02/06/2026
Check out the great program of the *1st Interdisciplinary Symposium on Meta Science for Methods Research* organized 31 August and 1 September in Zürich! Ton of cool speakers and meta-methodological reseach! crsuzh.pages.uzh.ch/msmr/program/ (registration still open)
crsuzh.pages.uzh.ch
index – MSMR 2026
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František Bartoš @fbartos.bsky.social · 16/05/2026
I am not sure I will write a preprint about this in particular, but I will post about the new package version!
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František Bartoš @fbartos.bsky.social · 15/05/2026
Possibly within 2 months with all remaining metafor style 'random' argument functionality
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František Bartoš @fbartos.bsky.social · 13/05/2026
The implementation is available in both RoBMA R package (via the `cluster` argument) and in @jaspstats.bsky.social !
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František Bartoš @fbartos.bsky.social · 13/05/2026
Interestingly, we find that in a presence of a correlation between cluster size and effect size (as we observed in our second example), most existing methods become severely biased; multilevel RoBMA was the only method to consistently recover the true effect across all simulated conditions.
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František Bartoš @fbartos.bsky.social · 13/05/2026
We illustrate the method on two re-analyses (see vignettes: cran.r-project.org/web/packages... and cran.r-project.org/web/packages...) and two simulation studies.
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František Bartoš @fbartos.bsky.social · 13/05/2026
Accounting for the multilevel structure in publication bias adjustment is necessary for drawing valid inferences since majority of meta-analyses include multiple effect sizes per study. Ignoring this dependency results in overly narrow intervals and inflated evidence.
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František Bartoš @fbartos.bsky.social · 13/05/2026
This extension fully connects with other features available in RoBMA, e.g., meta-regression, estimated marginal means, etc, making it directly applicable to the usual meta-analytic workflows.
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František Bartoš @fbartos.bsky.social · 13/05/2026
The multilevel extension to RoBMA was just published in BRM (link.springer.com/article/10.3...). Together with @maxmaier.bsky.social and EJ Wagenmakers, we developed a 3-level version of RoBMA which allows analysts to adjust for publication bias in meta-analyses with estimates nested within studies.
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František Bartoš @fbartos.bsky.social · 12/05/2026
It is, unfortunatelly, not the only poorly conducted meta-analysis on the effect of LLMs on learning in the literature. We have also examined 67 meta-analyses with 1,840 effect sizes showing the same patern across the literature. osf.io/preprints/ps...
osf.io
OSF
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František Bartoš @fbartos.bsky.social · 12/05/2026
I just found out that a meta-analysis on the effect of ChatGPT on learning that we criticized last year not adjusting for publication bias and overinterpreting the conclussions (osf.io/preprints/ps...) was retracted last month (see notice www.nature.com/articles/s41...)!
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František Bartoš @fbartos.bsky.social · 08/05/2026
I have several new upgrades in mind like - flexible random effects structures - coefficient hypothesis tests - multiple inputation in plans!
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František Bartoš @fbartos.bsky.social · 08/05/2026
These update unfortunatelly break backwards compatibility and the syntax no longer matches the previously published tutorials. Fully updated vignettes showcasing how to match the previous versions of the package are on the github pages at: fbartos.github.io/RoBMA/index....
fbartos.github.io
Robust Bayesian Meta-Analyses
A framework for Bayesian meta-analysis, including model estimation, prior specification, model comparison, prediction, summaries, visualizations, and diagnostics. The package fits single and model-ave...
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František Bartoš @fbartos.bsky.social · 08/05/2026
More flexible publication bias adjustment. The new prior_weightfunction() allows setting custom priors on the selection models (fbartos.github.io/RoBMA/articl...)
fbartos.github.io
Publication-Bias Adjustment
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František Bartoš @fbartos.bsky.social · 08/05/2026
All fitting functions (RoBMA, BMA, BMA.glmm, brma, brma.glmm, bselmodel, bPET, bPEESE) recieve following arguments: - `mods` specify moderation (meta-regression) - `scale` specify scale-models - `cluster` allows effects nested within studies (`random` like in rma.mv arrives later)
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František Bartoš @fbartos.bsky.social · 08/05/2026
New default prior distributions: the `measure` argument allows specifying default priors based on unit information standard deviation (UISD). For general (nonstandardized effect size measures), those can be estimated from samples sizes and ses directly (fbartos.github.io/RoBMA/articl...)
fbartos.github.io
Prior Distributions
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František Bartoš @fbartos.bsky.social · 08/05/2026
A major release of the RoBMA package (4.0.0) is now on CRAN. Main highlights: - fully redesigned interface closely matching metafor - dedicated brma, bselmodel, bPET, bPEESE for single model fits - fit diagnostics features (residuals, influence, etc) (overview at fbartos.github.io/RoBMA/articl...)
fbartos.github.io
Feature Coverage
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František Bartoš @fbartos.bsky.social · 07/05/2026
See arxiv.org/abs/2604.21596 for details!
arxiv.org
Efficient Bayes Factor Sensitivity Analysis via Posterior Density Ratios
Bayes factor sensitivity analysis examines how the evidence for one hypothesis over another depends on the prior distribution. In complex models, the standard approach refits the model at each hyper-p...
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František Bartoš @fbartos.bsky.social · 07/05/2026
What makes it even more efficient is combining this trick with inverse weighted marginal density estimator (IWMDE). In out settings IWMDE becomes trivial to implement and improves the density estimation tremendously so only a couple thousands posterior samples are needed.
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František Bartoš @fbartos.bsky.social · 07/05/2026
In our new preprint we show how to efficiently compute Bayes factor sensitivity analyses for any model comparison. The computation trick is simple -- it rellies on extend the model by a hyper-prior on the parameter(s) for which sensitivity is desired and using transitivity of Bayes factors.
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Reposted by František Bartoš
Victor Shiramizu @victorshiramizu.bsky.social · 19/03/2026
Our paper is now out in Hormones and Behaviour. We found little evidence for group differences in 2D:4D ratios by sexual orientation when jointly modeling publication bias and heterogeneity. w/ @fbartos.bsky.social, Ben Jones & @tvpollet.bsky.social www.sciencedirect.com/science/arti... 🧵1/9
sciencedirect.com
Little evidence for group differences in 2D:4D ratios based on sexual orientation after adjusting for publication bias
The ratio between the lengths of the second and fourth digits (2D:4D) has been proposed as a putative marker of prenatal androgen exposure and investi…
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Reposted by František Bartoš
Prof Andy Field @profandyfield.com · 26/02/2026
Interested in finding out more about @jaspstats.bsky.social? The Psych Methods Group at the University of Amsterdam is running four hands-on workshops (in person or online) this summer (@ejwagenmakers.bsky.social, @fbartos.bsky.social). More information at jasp-stats.org/workshops/ but to sum up:
jasp-stats.org
Workshops - JASP - Free and User-Friendly Statistical Software
The JASP team is excited to support four workshops this year (2026). Each of these workshops can be attended either in person (at the University of Amsterdam) or online: On Monday August 24th, we orga...
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Reposted by František Bartoš
Daniel Lakens @lakens.bsky.social · 10/02/2026
Everything is ready for the Perspectives on Scientific Error conference that starts tomorrow in Leiden! I look forward to hanging out with the mix of metascientists, philosophers of science, and statisticians! So many old friends will be there (and hopefully some new ones)! #PSE8
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František Bartoš @fbartos.bsky.social · 06/02/2026
Come to Amsterdam or join online for the full week of JASP workshops (24th-28th of August)! If you can't do the full week or you are only interested in meta-analysis, I will be giving the Meta-Analysis workshop on 25th of August. jasp-stats.org/2026/02/05/h...
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Reposted by František Bartoš
Björn Siepe @bsiepe.bsky.social · 04/02/2026
Does it make sense to preregister simulation studies? This question has sparked a lot of debate. ▶️We* work through the why, when, and how ▶️We discuss different phases of methodological research to clarify where preregistration might (or might not) add value 📝 Preprint: doi.org/10.31234/osf...
Diagram showing four phases of methodological research (Theory, Exploration, Systematic Comparison, Evidence Synthesis) with an arrow indicating that preregistration usefulness increases from early to late phases. Each phase lists its aim, elements, outcome, and an example from factor retention research.
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František Bartoš @fbartos.bsky.social · 28/01/2026
Does it mean that AI/LLMs do not help at education? I personally don't think so. I'm using the AI every day and find it incredibly useful. It would be odd if they didn't help at learning at all. However, the current empirical base does not substantiate strong claims.
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František Bartoš @fbartos.bsky.social · 28/01/2026
Meta-analysis level re-analysis then further highlights the issue of publication bias. Extremely overstated evidence (left) and mean effect size estimates (middle) due to a large degree of publication bias (right).
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