R-multiverse Production repository r-multiverse.org/production.h... looks great for those who prefer CRAN level stability (actually a bit more stable) for R packages, but want to also use high quality packages that are not in CRAN (like CmdStanR)

Whoa—my book is up for pre-order! 𝐌𝐨𝐝𝐞𝐥 𝐭𝐨 𝐌𝐞𝐚𝐧𝐢𝐧𝐠: 𝐇𝐨𝐰 𝐭𝐨 𝐈𝐧𝐭𝐞𝐫𝐩𝐫𝐞𝐭 𝐒𝐭𝐚𝐭 & 𝐌𝐋 𝐌𝐨𝐝𝐞𝐥𝐬 𝐢𝐧 #Rstats 𝐚𝐧𝐝 #PyData The book presents an ultra-simple and powerful workflow to make sense of ± any model you fit The web version will stay free forever and my proceeds go to charity. tinyurl.com/4fk56fc8

NordStat will be in Helsinki in 1-4 June, 2026. Website and preliminary program have been published: www.helsinki.fi/en/conferenc...

MC Stan is here! Follow for the latest Stan news, and tag if you want us to repost your posts about new papers, packages, courses, etc. about Stan

Stats and ML postdoc and permanent hiring season officially open at Flatiron statmodeling.stat.columbia.edu/2025/09/16/s...

for the late nite crew: stat_manual() is super good

Our paper, “Optimal pandemic control strategies …” bmcglobalpublichealth.biomedcentral.com/articles/10.... w @nickirons.bsky.social, just published.Takeaway: U.S. COVID-19 school closures were not cost-effective, but other measures were. medicalxpress.com/news/2025-09...

I am beyond excited to announce that ggplot2 4.0.0 has just landed on CRAN. It's not every day we have a new major #ggplot2 release but it is a fitting 18 year birthday present for the package. Get an overview of the release in this blog post and be on the lookout for more in-depth posts #rstats

The Journal-to-Conference track is back at AISTATS🌴! The track invites authors of papers published or accepted after January 1st, 2024 in AoS, Biometrika, JASA, JMLR and JRSS B to present their work as posters at #AISTATS2026 in Tangier, Morocco (May 2nd-5th 2026). 📅 Deadline: 31 January 2026

Simon Wood, the GOAT of generalized additive models & creator of the mgcv #rstats package, has an Annual Review of Statistics essay on GAMs, available open access #statssky #mlsky www.annualreviews.org/content/jour...

💡 Explore how practices from distributed, open-source software can make science more professional, open, and collaborative! Attend the “Science as amateur software development” lecture by Prof. Dr. @rmcelreath.bsky.social on Wed 17 Sept, 9:00. 👉 Register here: www.pretix.osc.lmu.de/lmu-osc/OSSS...

We are seeking a postdoctoral researcher in statistics to develop methods for analyzing large scale biodiversity and ecosystem function data at the University of Helsinki. This is a great opportunity for someone who wants to do advanced Bayesian modeling with direct link to real world applications.

bayesplot 1.14.0 CRAN release mc-stan.org/bayesplot/ with contributions from @tjmahr.com, Behram Ulukır, and @teemusailynoja.bsky.social My favorite new feature is the discrete style ppc_rootogram() as proposed in teemusailynoja.github.io/visual-predi... and shown below 1/3

Productive procrastination by making 7 PRs to fix Stan doc issues (still couple issues I think I can help with)

Stan / CmdStan 2.37 release! blog.mc-stan.org/2025/09/02/r... - sum_to_zero_matrix type sums to zero across both rows and columns - simplex and *_stochastic_matrix types should be now faster and more stable - new functions exposing the built-in constraint implementations 1/2

My Bayesian Data Analysis course at Aalto is starting in 20mins. There are now 375 registered students, but as the course is not compulsory for most, I expect about 230 students to finish it. All the course material is available online at avehtari.github.io/BDA_course_A...

I think we'll get the Bayesian workflow book finished this year (and keep it under 500 pages). It's just polishing work now

I finally tried out {priorsense}📦 with #Stan #rstats and it's awesome! Fed it a simple model I use for teaching, and found some (minor) prior-data conflicts. The powerscale_plot_dens() function really helps in understanding how "bad" the conflict is.

Aalto University course "Distributed Algorithms" starts tomorrow! All course material (including an online textbook and short videos) are freely available here: jukkasuomela.fi/da2020/

🚨AISTATS workshop proposals open! Big News: For the first time, there will be a day of workshops at #AISTATS 2026, in Tangier, Morocco 🌴🇲🇦 Quentin Berthet @qberthet.bsky.social and I are workshop chairs. virtual.aistats.org/Conferences/... Deadline: Oct 17, AOE

Nice looking paper

Preprint and the website by @dingdingpeng.the100.ci and @vincentab.bsky.social are great, and I got inspired to illustrate Bayesian workflow for model checking and comparison *before* model interpretation following their friendship importance example users.aalto.fi/~ave/casestu...

Bridge sampling estimates marginal likelihood. A recommendation has been to use an order of magnitude more posterior draws than otherwise. With Giorgio Micaletto we show how to compute MCSE for bridge sampling to decide how many draws are actually needed arxiv.org/abs/2508.14487

There is a new release candidate 2.37.0-rc3 for CmdStan / Stan. If you have big Stan models, help us to test the release candidate by compiling and fitting your models (I already caught one bug with my birthdays models). See installation instructions at discourse.mc-stan.org/t/cmdstan-st...

Happy to announce ✨quarto-revealjs-editable✨ This fully supersedes the imagemover extension, as I back then didn't realize the potential. You can now also move, resize, change font size and alignment for text in your slides github.com/EmilHvitfeld... #quarto #slidecrafting

I got an amusing error message from Eigen: "DenseBase::resize() does not actually allow to resize."

Now on CRAN, ggdiagram is a #ggplot2 extension that draws diagrams programmatically in #Rstats. Allows for precise control in how objects, labels, and equations are placed in relation to each other. wjschne.github.io/ggdiagram/ar...

Are you interested in Bayesian Optimization? Do you think multi-arm bandits are cool? Do you like donating to good causes? We'll, I'm super excited to say I'll be hosting a charity workshop on Bayesian Optimization with Multi-Arm Bandits on October 23rd. sites.google.com/view/dariia-...

{tinytable} 0.13.0 for #RStats can now draw interactive tables with sorting, filtering & pages! And the 📦 is still an ultra-simple, powerful, and 0-dep way to create beautiful tables in basically any format: tex, typ, docx, pdf, png, md, etc Gallery & Docs: vincentarelbundock.github.io/tinytable/

😮

During the summer someone asked how to compute Monte Carlo error interval when the target distribution is known to have finite mean, but infinite variance, as then the usual variance based MCSE doesn't work. A good solution is to use Pareto smoothing and then compute MCSE as usual 1/

For a few years, I've occasionally suffered from zombie invasions. Web searches did not find others with similar problem. It was clearly related to parallelization, but there was no clear logic when. Together with Noa Kallioinen, we finally figured it out. 1/

Announcing my forthcoming short paper at #ieeevis! In this solo-author work, I examine and critique the logic of generalization about decision support in visualization research. arxiv.org/abs/2508.06751

Excited to share my newest quarto revealjs plugin: imagemover Easily reposition and resize images directly in your quarto revealjs slides for a much smoother slidecrafting experience github.com/EmilHvitfeld... #quarto

Posterior predictive checking of binary, categorical and many ordinal models with bar graphs is useless. Even the simplest models without covariates usually have such intercept terms that category specific probabilities are learned perfectly. Can you guess which model, 1 or 2, is misspecifed? 1/4

📣 Please share: We invite submissions to the 29th International Conference on Artificial Intelligence and Statistics (#AISTATS 2026) and welcome paper submissions at the intersection of AI, machine learning, statistics, and related areas. [1/3]

Reminder that all three books I've co-authored are freely available online for non-commercial use (and the fourth will be, too)

The Journal of Open Source Software (@joss-openjournals.bsky.social‬) is looking for editors. Come join our team! I've only been an editor for a few months, but I love working with JOSS. Our peer review process is actually collaborative, and we're Diamond Open Access. #AcademicSky 🧪 ⚗️ #CompChem

Looking for a Research Scientist at Google DeepMind with expertise in weather forecasting AND machine learning AND software engineering job-boards.greenhouse.io/deepmind/job...

It's sometimes difficult to get the focus needed for book writing, but this place was perfect for me

Based on this photo from 1920's at Helsinki University of Technology (which was later merged to Aalto University), they were also teaching how to draw an owl! (cc @rmcelreath.bsky.social)

💻 This was also my first time using Stan playground (github.com/flatironinst...) to teach a class! Thank you Brian Ward for creating this tool and helping me set it up for the class!

Paper recommendation: A sparse modelling approach for analyzing community dynamics (20-40 species), using a regularized horseshoe prior for N² species interactions (zero vs non-zero), and a dimension-reduction approach for the N² residual correlation matrix (influences of unmeasured covariates) 🔥

While I was on vacation enjoying Finnish summer, Frank Weber finished some PRs and made a new major CRAN release of projpred mc-stan.org/projpred/ (for projection predictive variable selection). This release contains some major features add by me and Frank. 1/4

How can we reform science? I have some ideas. But I am not sure you’ll like them, because they don’t promise much. elevanth.org/blog/2025/07...

Javier Enrique Aguilar, David Kohns, Aki Vehtari, Paul-Christian B\"urkner R2 priors for Grouped Variance Decomposition in High-dimensional Regression https://arxiv.org/abs/2507.11833

🔍 Most Bayesian models aren’t properly checked Even when they converge, they might be wrong in ways you won’t see—unless you look differently In this episode, Teemu Säilynoja joins @alex-andorra.bsky.social to explore, SBC, prior predictive checks and more! 🎧 learnbayesstats.com/episode/135-...

I wrote a blog post to celebrate 10 years of loo package 🎉 (R package implementing fast Pareto smoothed importance sampling cross-validation and many other useful methods for cross-validation)

New manuscript by Nawaf Bou-Rabee, Bob Carpenter, Tore Kleppe and Sifan Liu on the WALNUTS algorithm which improves of the NUTS sampler by introducing a locally adaptive step size. 📜 Paper: arxiv.org/pdf/2506.18746 💻 Code: github.com/bob-carpente...

I wrote a blog post to celebrate 10 years of loo package 🎉 (R package implementing fast Pareto smoothed importance sampling cross-validation and many other useful methods for cross-validation)