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Tomi Capretto

@tomicapretto.bsky.social
117 followers 135 following 15 posts

Statistician and OSS developer, mainly: Bambi, PyMC and ArviZ. tomicapretto.com

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Tomi Capretto @tomicapretto.bsky.social · 02/07/2026
The PyMC blog isn’t known for being super active, but an excellent post summarizing all the great new stuff in PyMC 6 and PyTensor 3 landed a while ago. Enthusiastic PyMC users, this is a must-read: www.pymc.io/blog/pymc_v6...
pymc.io
PyMC 6.0 & PyTensor 3.0: ecosystem updates
PyMC has been under steady development since the early 2010s. To mark the new major releases of PyMC 6.0 and PyTensor 3.0, we want to highlight the developments across the PyMC ecosystem(and its cl...
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Aki Vehtari @avehtari.bsky.social · 26/06/2026
@aloctavodia.bsky.social has been porting Bayesian Workflow book avehtari.github.io/Bayesian-Wor... case studies to Python using CmdStanPy, numpyro, ArviZ, Bambi, and kulprit arviz-devs.github.io/bayesian-wor... He is working on porting the rest of the case studies, too
arviz-devs.github.io
Bayesian Workflow book: Case studies in Python – Bayesian Workflow case studies in Python
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Aki Vehtari @avehtari.bsky.social · 23/06/2026
New paper "To select or not to select: predictively consistent priors instead of model selection" with Anna Elisabeth Riha, Leevi Lindgren, @davidkohns.bsky.social, @paulbuerkner.com arxiv.org/abs/2606.22850 Model selection is not a substitute for building good models in the first place 1/
To select or not to select: predictively
consistent priors instead of model selection

Anna Elisabeth Riha, Leevi Lindgren, David Kohns, Paul-Christian Bürkner, Aki Vehtari

Bayesian modelling workflows often consider multiple candidate models of varying complexity. Model selection is commonly used to navigate potential trade-offs between model complexity and generalisability to new data. We study when model selection is unnecessary or can even be harmful for predictive performance in finite data regimes and find that the need for selecting simpler models can depend on prior choice. We formalise predictively consistent priors, which keep prior predictive implications stable as model complexity increases. Across examples and numerical experiments, including adding covariates in linear and logistic regression, forward variable selection, and nonlinear modelling, flexible models with predictively consistent priors typically match or outperform selected simpler models in out-of-sample predictive performance. When selection helps, it can indicate poor joint prior implications, such as excessive prior mass on implausible predictive values. Based on our findings, we propose replacing the notion of sparsity or parsimony at the level of model components with specifying priors that remain sensible in predictive space as models become more complex.
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Tomi Capretto @tomicapretto.bsky.social · 21/06/2026
I don't understand Slack. I opened it after months and, as expected, I had to log in. What I didn't expect was that I had to log in to every workspace, all using the same e-mail address. It seems that was not enough, as Slack decided I had to copy/paste a security code in every log in attempt.
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Chelsea Parlett @chelseaparlett.bsky.social · 12/06/2026
The goal should never be "use ai ", the goal is "solve X problem" and sometimes ai could be a tool to do that
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ArviZ @arviz.bsky.social · 07/04/2026
ArviZ now has built-in tools for prior & likelihood sensitivity analysis via power-scaling! Instead of fitting multiple models with different priors, you fit once and use importance sampling to approximate the effect of perturbing the prior or likelihood.
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ArviZ @arviz.bsky.social · 01/04/2026
ArviZ 1.0 brings a lot of new plotting functionality. Check our gallery for a glimpse of what's new: python.arviz.org/projects/plo...
python.arviz.org
Example gallery — arviz-plots dev documentation
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Andrew Gelman et al. @statmodeling.bsky.social · 20/03/2026
A data model is not just a “likelihood” statmodeling.stat.columbia.edu/2026/03/20/a...
statmodeling.stat.columbia.edu
A data model is not just a “likelihood” | Statistical Modeling, Causal Inference, and Social Science
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ArviZ @arviz.bsky.social · 19/03/2026
ArviZ 1.0 is out! We have refactored it to be more modular, flexible & lightweight. For an overview of the changes, check the migration guide. python.arviz.org/en/stable/us...
python.arviz.org
Getting started — ArviZ 1.0.0 documentation
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Tomi Capretto @tomicapretto.bsky.social · 20/01/2026
It took my just 7 years of Python coding to embrace the power of `breakpoint()`. Feels so great!
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Alexandre Andorra @alex-andorra.bsky.social · 02/01/2026
This one is a foundational one: #ExperimentalTrialDesign the ̶r̶i̶g̶h̶t̶ Bayesian way, with no other than Scott Berry, from Berry Consultants, LLC! Enjoy, and happy new year, my dear Bayesians 🖖
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Alexandre Andorra @alex-andorra.bsky.social · 02/01/2026
My #AdvancedRegressionModeling course, written with the brilliant Ravin Kumar and @tomicapretto.bsky.social, is now available through my Topmate profile! So do give it a try and let me know what you think in the comments 👇 See you soon in the Intuitive Bayes' Discourse 🖖 topmate.io/alex_andorra...
topmate.io
Your All-in-One Creator Storefront
Make money from your content. Sell products, host sessions, and grow your business — all from a single link.
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The R Foundation @r-foundation.bsky.social · 10/12/2025
The R Foundation is happy to be a partner on the project "Enabling the next generation of R contributors" awarded £500k under the Research Software Maintenance Fund (Software Sustainability Institute, UK). Announcement: www.software.ac.uk/ssi-awards-f... Congratulations to the project team!
software.ac.uk
SSI awards funding to 13 projects through the RSMF Round 1 | Software Sustainability Institute
We are pleased to announce that the Research Software Maintenance Fund (RSMF) has funded 13 projects to advance the sustainability and impact of research software. Through this initiative, the SSI, wi...
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Stefano @stippe87.bsky.social · 07/10/2025
Modelling nested factors in Bambi+PyMC #stats thestippe.github.io/statistics/n...
thestippe.github.io
Nested factor
Saving yourself from mis-labelling
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Tomi Capretto @tomicapretto.bsky.social · 26/09/2025
If you had to bet against a free throw, would you bet against the first or the second attempt? What if the player were a rookie? And what if it were a specific rookie? Let's try to find out. tomicapretto.com/posts/2025-0...
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Tomi Capretto @tomicapretto.bsky.social · 09/08/2025
TIL in Python about any("") all("") any([]) all([]) 🤯
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Tomi Capretto @tomicapretto.bsky.social · 24/07/2025
Attempted to execute a cell in a Jupyter Notebook in Positron to see what the dependency installation process was like... It just worked, no extra dependencies, just Python. Python data science tooling is healing.
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Tomi Capretto @tomicapretto.bsky.social · 07/07/2025
Empecé con R/RStudio y fue un bajón cambiar de IDE para Python (terminé en VS Code). Hace poco salió la 1° versión estable de Positron, que mezcla lo mejor de RStudio y VS Code. Como pronto arranco a dar un curso en Python, armé tutorial de instalación: www.youtube.com/watch?v=9orV...
youtube.com
Descargar, instalar y usar Python y Positron en Windows
YouTube video by Tomas Capretto
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Tomi Capretto @tomicapretto.bsky.social · 06/06/2025
Polars is so beautiful I can't look at pandas data processing without my eyes bleeding
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Mine Doğucu @minedogucu.com · 05/04/2025
Please help us spread the word to teachers about StatisticsTeacher.org @amstatnews.bsky.social @nctm.org #statsed #nctm #math #statistics
Text of the image reads “You can find articles and free lesson plans specifically for teaching statistics and data science in K-12. Check out StatisticsTeacher.org. Consider submitting your own article and lesson plan.
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Allen Downey @allendowney.bsky.social · 26/03/2025
At PyMC Labs I've been working with a group developing synthetic consumers for marketing research. We just published this white paper with an overview of work in this space -- and we have a blog post coming next week with some experimental results. www.pymc-labs.com/blog-posts/s...
pymc-labs.com
Synthetic Consumers: The Promise, The Reality, and The Future - PyMC Labs
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Nathaniel Forde @nathanielforde.bsky.social · 24/01/2025
Looking forward to this! Talking about the do-operator and structural causal models in PyMC
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Alexandre Andorra @alex-andorra.bsky.social · 24/01/2025
Really fantastic to host Jesse Grabowski on the show! I learned so much about #TimeSeries thanks to him. And there is still so much I don't know, so I guess you'll have to come back very soon Jesse ;)
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Alexandre Andorra @alex-andorra.bsky.social · 21/01/2025
🚨 **Big News!** 🚨 The first two lessons of our Intuitive Bayes courses are now FREE! 🎉 Try them out to make sure they're the perfect fit before diving into the full experience
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Pierre-Simon Laplace @learnbayesstats.bsky.social · 11/01/2025
💯What if Bayesian modelling could be faster, more flexible, and easier to interpret? 🎧 youtu.be/7POdNknJ1Es?... 🎙️ Episode 123 is here! @alex-andorra.bsky.social chats with @aloctavodia.bsky.social about ground breaking tools and ideas that are shaping the future of Bayesian workflows. #LBS #BART
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Alexandre Andorra @alex-andorra.bsky.social · 10/12/2024
Max Göbel and I recently submitted a paper to the MIT Sloan Conference. We're using #HSGPs to isolate ⚽ players' contribution from team effects and introduce Skill- and Performance Above Replacement metrics. Paper is still WIP, but we put it on Arvix to get first feedback! arxiv.org/abs/2412.05911
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Tomi Capretto @tomicapretto.bsky.social · 03/12/2024
Mom, I love Polars
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