František Bartoš

František Bartoš

@fbartos.bsky.social

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

927 followers206 following135 posts

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We released two preprints describing the JASP Meta-Analytic functionality in detail. Meta-Analysis with JASP, Part I: Classical Approaches (arxiv.org/abs/2509.09845) Meta-Analysis with JASP, Part II: Bayesian Approaches (arxiv.org/abs/2509.09850)

arxiv.orgMeta-Analysis with JASP, Part I: Classical ApproachesMeta-analyses play a crucial part in empirical science, enabling researchers to synthesize evidence across studies and draw more precise and generalizable conclusions. Despite their importance, access...
František Bartoš@fbartos.bsky.social

The new version of JASP (0.95) containing another significant update to the Meta-Analysis module is out. You can perform state-of-the-art Bayesian publication bias-adjusted meta-regression in only a few clicks. A couple of additional clicks get you publication-ready figures!

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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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...

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 ...

František Bartoš reposted

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.jobsPhD 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...

My supervisor vibecoded a nice visualization for the same-side bias in coin flips effect:

bayesianspectacles.orgCoin precession simulation with same-side fraction
ejwagenmakers.bsky.social@ejwagenmakers.bsky.social

Fair coins tend to land on the same side they started, but why? The Wobbly Coin Flip Simulator allows you to see the coin spin around its axis: www.bayesianspectacles.org/wp-content/u.... See also www.bayesianspectacles.org/why-fair-coi... (simulation courtesy of ChatGPT Pro)

Join the JASP workshops at the last week of August!

JASP@jaspstats.bsky.social

We still have a few spots left for our 2026 version of the hybrid JASP Workshop week end of August featuring a day on Discovering Statistics, a day on State-of-the-art Meta Analyses, a day on Machine learning, and two days on Bayesian hypothesis testing😊 (also single days) jasp-stats.org/workshops/

- 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

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 ...

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!

František Bartoš reposted

František Bartoš reposted

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.ioOSF

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)

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.orgWorkshops - JASP - Free and User-Friendly Statistical SoftwareThe 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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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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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.

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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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.ioRobust Bayesian Meta-AnalysesA 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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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)

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.

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.

František Bartoš reposted

František Bartoš reposted

František Bartoš reposted

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

František Bartoš reposted

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...