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!

Meta-Analysis with JASP, Part I: Classical Approaches (Example 1)

YouTube video by JASP Statistics

youtube.com

Join the JASP workshops at the last week of August!

JASP@jaspstats.bsky.social · 2w ago

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/

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:

@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).

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!

Want to learn JASP? My colleagues (@ejwagenmakers.bsky.social) at UVA are running workshops in August: jasp-stats.org/2026/02/03/h...

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“....

jasp-stats.org

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

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...)

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/

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...

jasp-stats.org

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)

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.

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...)!

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...)

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.

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

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…

sciencedirect.com

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:

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...

jasp-stats.org

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

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...

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...

We just posted a preprint with a comprehensive meta-meta-analysis of the effects of AI/LLMs on learning. TLDR: - 1,840 effect sizes - extreme between-study heterogeneity - extreme publication bias - small average effects (three times lower than usually reported) (osf.io/preprints/ps...)

Edgeworth proposed the alpha=.005 criterion 134 years prior to Benjamin et al. (2019). :-) www.bayesianspectacles.org/redefine-sta...

Redefine Statistical Significance Part XXI: Edgeworth Proposed the .005 Criterion Back in 1885

The statistical significance test was not invented by Ronald Fisher. The key idea was already laid out by Francis Ysidro Edgeworth (1845-1926), whose 1885 article “Methods of statistics&#8221…

bayesianspectacles.org

The world's earliest recorded outlier? Let me know if you have an even older example! www.jasp-services.com/jasp-for-qua...

JASP for Quality Control, Example 6: The World's Earliest Recorded Outlier? - JASP Services BV

Information hidden in raw data can be revealed most easily by means of statistical visualization techniques (“always plot your data”). To demonstrate I will now analyze the duration of reign (in years...

jasp-services.com

"we did not find any evidence for publication bias (p=0.077)"

The Robust Bayesian Meta-Analysis package got updated with additional vignettes explaining how to perform Bayesian model-averaged publication bias-adjusted - multilevel meta-analysis (cran.r-project.org/web/packages...) - multilevel meta-regression (cran.r-project.org/web/packages...)

I recently bought 20 bags of potato that, according to the Albert Heijn supermarket, should each contain 1 kg. This turns out to be *false*. www.jasp-services.com/at-the-alber...

At the Albert Heijn, You Get About 2% More Potatoes Than What it Says on the Label - JASP Services BV

A week ago I started a small quality control project where I measured twenty “1 kg” Albert Heijn (AH) potato bags in order to assess whether or not AH is systematically underfilling them, as some soci...

jasp-services.com

The suspense is building: do the measurements of 20 units indicate that the Albert Heijn underfills its 1 kg bags of potatoes? An interim post on the importance of articulating your predictions *before* seeing the results. :-) www.jasp-services.com/do-the-1kg-a...

Do the 1kg Albert Heijn Potato Bags Really Contain 1kg of Potatoes? - JASP Services BV

A few days ago I announced a small quality control project where I would measure 20 bags of “1 kg” Albert Heijn (AH) potato bags to assess whether or not AH is systematically underfilling them, as som...

jasp-services.com

This week's blog post features "raincloud plots", a relatively recent development in data visualization. Will the raincloud plot gradually replace the box plot? It just might! Check out the raincloud plot for the planets in our solar system at www.jasp-services.com/jasp-for-qua...

JASP for Quality Control, Example 4: The Raincloud Plot - JASP Services BV

In our last post we discussed the boxplot of the distances to the sun for each of the eight planets in our solar system, as measured in astronomical units (AU; AU=1 is the average distance from the ea...

jasp-services.com

We just preprinted a huge meta-meta-analysis examining the effects of exercise on cognition, memory, and executive function In short - 2239 effect sizes - extreme between-study heterogeneity - extensive publication bias - some subgroup/exercise-specific effects More below (doi.org/10.31234/osf...)

Feb 16-17: JASP Hackathon in Amsterdam! Now open for applications Post with details on the JASP website: jasp-stats.org/2025/11/21/a...

Apply for the eScience JASP Hackathon and Build Your Own Module, in Amsterdam - JASP - Free and User-Friendly Statistical Software

tldr; On 16-17 February 2026 the Netherlands eScience Center is hosting a two-day JASP hackathon in Amsterdam. The purpose of the hackathon is to guide participants into developing their very own JASP...

jasp-stats.org

New blogpost on our JRR website! Check out our new blogpost (link below): we highlight a study for re-analysis on whether CEOs are shaped by their daughters. This could be a potential candidate for a robustness report. www.journalofrobustnessreports.org/are-ceos-sha...

Are CEOs Shaped by Their Daughters? - Journal of Robustness Reports

In this blogpost I wish to highlight the following article as a candidate for a set of Robustness Reports: Cronqvist, H., & Yu, F. (2017). Shaped by their daughters: Executives, female socialization, ...

journalofrobustnessreports.org