Aki Vehtari

All four books I've co-authored are freely available online for non-commercial use: - Bayesian Workflow at avehtari.github.io/Bayesian-Wor... Links to other three books are in the quoted post 👇 (too many books to fit in one post!)

After quite a long time sitting as a development package epidist is now on CRAN. It extends brms with a framework for epidemiological extensions.

I recently moved to TU Darmstadt (Germany) and am currently hiring PhD student through ELISS. https://ellis.eu/news/ellis-phd-program-call-for-applications-2026 If you interested, please apply and choose me as a potential advisor. Topics include Continual/Distributed/Federated/Active/Transparent […]

CmdStanR 1.0 release candidate is now available! There are a lot of changes! Please read more and help testing discourse.mc-stan.org/t/cmdstanr-1... (CmdStanR is an R interface for using Stan via CmdStan)

How can we make Bayesian inference faster? 🎧 In Episode 167 @alex-andorra.bsky.social @paulbuerkner.com and Steve Bronder discuss amortized inference, neural posteriors, GPUs in Stan, and GPU-ready linear algebra. Recorded live at StanCon 2026 in Uppsala! 🔗 lnkd.in/dUTHWeq3 #BayesianStatistics

TIL that cran is "A measure of capacity for fresh herrings as caught; fixed by the Fisheries Board at 371/2 gallons (about 750 fish)." (Oxford English Dictionary).

In search of top talent - the call for new HiLIFE Tenure Track professors is open www.helsinki.fi/en/hilife-he...

We have a University Lecturer in Ecology position open at the Department of Organismal and Evolutionary Biology at the University of Helsinki: jobs.helsinki.fi/job/Helsinki... The closing date for applications is 6 November 2026 at 23.59 (EET). Please spread the word in your networks.

Another thing I really liked from @rmcelreath.bsky.social’s talk yesterday: he introduced #BayesianWorkflow, with Andrew Gelman, Aki Vehtari et al. It’s much more than just #Bayesian inference: … 1/2

Hey—we’re hiring two postdocs! statmodeling.stat.columbia.edu/2026/10/06/h...

Bayesian Workflow code is at the Bayesian Workflow website! statmodeling.stat.columbia.edu/2026/10/05/b...

priorsense: an R package for prior and likelihood sensitivity checks v1.4.0 is now on CRAN News: - joined the @mc-stan.org project. Docs at mc-stan.org/priorsense and dev at github.com/stan-dev/pri... - reviewed by @ropensci.org - paper in @joss-openjournals.bsky.social - more vignettes

Release of CmdStan 2.40, including new Stan Math, core Stan, and Stanc, is now available! Blog post with new features blog.mc-stan.org/2026/09/16/r... Highlights - integrate_1d_double_exponential, a variadic version of old integrate_1d - integrate_1d_gauss_kronrod, a different quadrature rule ...

"Recommendations for visual predictive checks in Bayesian workflow" published in Journal of Visualization and Interaction doi.org/10.54337/jov..., which is exciting also because this is our first Quarto html journal paper www.journalovi.org/2025-sailyno.... I wish more journals would adopt this!

I'm looking for doctoral students, postdocs and research fellows to work with on Bayesian Workflow. Flexible starting time

I will be looking for a PhD student in Bayesian statistics (in collaboration with Paul Bürkner), located in Prague. Forward to students if you have somebody who could be interested. www.martinmodrak.cz/grammo-call/

A FAQ is what to do in case of high Pareto-k's with PSIS-LOO or PSIS-LOGO. In case of hierarchical models we can integrate out group specific parameters before PSIS. We investigated reliability of some alternative integration methods with the eventual goal of automating this arxiv.org/abs/2609.05713

New paper in JMLR with Otto Tabell and Santtu Tikka: “Clustering and Pruning in Causal Data Fusion.” We derive conditions for reducing causal graphs while preserving conclusions about identifiability and non-identifiability. www.jmlr.org/papers/v27/2...

I'm looking for doctoral students, postdocs and research fellows to work with on Bayesian Workflow. Flexible starting time

During the many long term ecological change projects in @rececochange.bsky.social, we have concretely learned how important long term data are. Here some thoughts on the topic 👇 Long-Term Community Data Reveal Ecological and Evolutionary Phenomena - www.annualreviews.org/content/jour...

Xiang Ye's excellent Stan case studies for 1) new priors for circular distributions xiangyestats.github.io/directional-..., 2) and new models for circular targets xiangyestats.github.io/directional-... 3) and circular covariates xiangyestats.github.io/directional-... Links to papers included

As non-native English speaker from Finland it was interesting to test this, but I'm not surprised by the result

Big news! 🎉 𝚖𝚊𝚛𝚐𝚒𝚗𝚊𝚕𝚎𝚏𝚏𝚎𝚌𝚝𝚜 1.0.0 for #Rstats is out. It’s a big number and it feels like a big step. I wrote a blog on the challenges of interpreting statistical models, SPEED, cool new features, the future, and a 5 year package development and writing odyssey. arelbundock.com/posts/margin...

Last year, I publicly complained multiple times (see e.g. elevanth.org/blog/2025/07...) that the open access movement had been captured by publishers, and we are now worse off than before open access. Well people got mad at me for saying it. But I think things are still getting worse.

We made a systematic comparison of contemporary remote sensing techniques (RS) and species distribution modelling (SDM) in predicting spatial distribution of coastal habitats in seven European marine areas. www.sciencedirect.com/science/arti... 1/3

Now #hiring: postdocs and PhD students in AI & machine learning research. Deadline Sept. 21, 2026. - Cutting-edge computational resources like @lumi-supercomputer.eu - Close collaboration with @ellis.eu network - Ambitious, high-impact projects across Finland www.ellisinstitute.fi/postdoc-and-...

When does“variance explained” actually mean causation? In our new preprint, Olli Saarela and I develop graph-based causal variance decompositions. The framework clarifies when components of an ordered variance decomposition have causal interpretations. arxiv.org/abs/2608.27140

In this special episode of Learning Bayesian Statistics, @alex-andorra.bsky.social is joined by Andrew Gelman, Aki Vehtari, and Richard McElreath to discuss Bayesian Workflow. From simulation and hierarchical pooling to causal inference, there’s a lot to unpack 🎧 lnkd.in/geX2QkxV #Bayesian

We need reviewers for our submission to the Journal of Open Source Education. Our resource focuses on MCMC convergence, model checking, comparison, etc all powered by ArviZ. This is the issue where you can volunteer: github.com/openjournals...

In our latest study we show that Baltic Sea pelagic fish communities have changed their distribution over the past 17 years, consistent with projected climate-driven salinity reductions 👇 Community-level modelling of pelagic fish assemblages... academic.oup.com/icesjms/arti... 1/3

Watched Bob Carpenter's StanCon talk and decided the Stan stack deserved some love. PRs incoming to stan-math, stanc3, bridgestan + walnutpie: −15% walltime per gradient, a silent autodiff blowup on degenerate eigenvalues (ESS 29→411 when fixed), and a small pile of bugs 👀 :3 #rstats #stan

Given all the discussions about Laplace and Jacobians at StanCon, reminder also about my case study with simple visual illustrations users.aalto.fi/~ave/casestu...

Had a wonderful time at StanCon in Uppsala! Glad to connect with such a thriving Bayesian community. Many thanks to the organizers for putting together this cool event

Given all the discussions about Jacobians at #StanCon today, the @mc-stan.org audience would appreciate that {ggdist} automatically applies the Jacobian adjustment when visualizing densities on transformed scales -- I should have demoed it in my talk! Sometimes useful when looking at priors...

As of v2.39, Stan (@mc-stan.org) provides an embedded Laplace approximation for fitting latent Gaussian models. Thanks to the tremendous effort by Steve Bronder, @avehtari.bsky.social, @brianward.dev, and many others. 📽️ www.youtube.com/watch?v=DDTP... 🧵 1/

StanCon 2026 tutorial "Bayesian model diagnostics: Workflows and software tools" by Noa Kallioinen, @teemusailynoja.bsky.social and @aloctavodia.bsky.social is available online n-kall.github.io/stancon2026/

ELLIS Institute Finland PostDoc and doctoral student call is open (DL September 21, 2026). You can apply also to work with me on computational methods for Bayesian workflows www.ellisinstitute.fi/postdoc-and-...

And we have a new Stan contributor John Ashley Burgoyne who submitted his first PR github.com/stan-dev/mat... during the hackathon!