A couple years ago Wei and I published a paper, Difficulty of selecting among multilevel models using predictive accuracy, in which we . . . well, we discussed the difficulty of selecting among multilevel models using predictive accuracy. The paper happened as follows. We’d been fitting hierarchical logistic regressions of poll data and I had […]

**Statistical computing**category.

## 3 postdoc opportunities you can’t miss—here in our group at Columbia! Apply NOW, don’t miss out!

Hey, just once, the Buzzfeed-style hype is appropriate. We have 3 amazing postdoc opportunities here, and you need to apply NOW. Here’s the deal: we’re working on some amazing projects. You know about Stan and associated exciting projects in computational statistics. There’s the virtual database query, which is the way I like to describe our […]

## You’ll never guess what’s been happening with PyStan and PyMC—Click here to find out.

PLEASE NOTE: This is a guest post by Llewelyn Richards-Ward. When there are two packages appearing to do the same thing, lets return to the Zen of Python which suggests that: There should be one—and preferably only one—obvious way to do it. Why is this particular mantra important? I think because the majority of users […]

## Stan intro in Amherst, Mass.

Krzysztof Sakrejda writes: I’m doing a brief intro to Stan Thursday 4:30pm in Amherst at the University of Massachusetts. As the meetup blurb indicates I’m not going to attempt a full tour but I will try to touch on all the pieces required to make it easier to build on models from the manual and […]

## Stan PK/PD Tutorial at the American Conference on Pharmacometrics, 8 Oct 2015

Bill Gillespie, of Metrum, is giving a tutorial next week at ACoP: Getting Started with Bayesian PK/PD Modeling Using Stan: Practical use of Stan and R for PK/PD applications Thursday 8 October 2015, 8 AM — 5 PM, Crystal City, VA This is super cool for us, because Bill’s not one of our core developers […]

## Fitting models with discrete parameters in Stan

This book, “Bayesian Cognitive Modeling: A Practical Course,” by Michael Lee and E. J. Wagenmakers, has a bunch of examples of Stan models with discrete parameters—mixture models of various sorts—with Stan code written by Martin Smira! It’s a good complement to the Finite Mixtures chapter in the Stan manual.

## The Final Bug, or, Please please please please please work this time!

I’ve been banging my head against this problem, on and off, for a couple months now. It’s an EP-like algorithm that a collaborator and I came up with for integrating external aggregate data into a Bayesian analysis. My colleague tried a simpler version on an example and it worked fine, then I’ve been playing around […]

## Stan Puzzle #1: Inferring Ability from Streaks

Inspired by X’s blog’s Le Monde puzzle entries, I have a little Stan coding puzzle for everyone (though you can solve the probabilty part of the coding problem without actually knowing Stan). This almost (heavy emphasis on “almost” there) makes me wish I was writing exams. Puzzle #1: Inferring Ability from Streaks Suppose a player […]

## PK/PD Talk with Stan — Thu 8 Oct, 10:30 AM at Columbia: Improved confidence intervals and p-values by sampling from the normalized likelihood

Sebastian Ueckert and France Mentré are swinging by to visit the Stan team at Columbia and Sebastian’s presenting the following talk, to which everyone is invited. Improved confidence intervals and p-values by sampling from the normalized likelihood Sebastian Ueckert (1,2), Marie-Karelle Riviere (1), France Mentré (1) (1) IAME, UMR 1137, INSERM and University Paris Diderot, […]

## ShinyStan v2.0.0

For those of you not familiar with ShinyStan, it is a graphical user interface for exploring Stan models (and more generally MCMC output from any software). For context, here’s the post on this blog first introducing ShinyStan (formerly shinyStan) from earlier this year. ShinyStan v2.0.0 released ShinyStan v2.0.0 is now available on CRAN. This is […]

## Stan at JSM2015

In addition to Jigiang’s talk on Stan, 11:25 AM on Wednesday, I’ll also be giving a talk about Hamiltonian Monte Carlo today at 3:20 PM. Stanimals in attendance can come find me to score a sweet Stan sticker. And everyone should check out Andrew’s breakout performance in “A Stan is Born”. Update: Turns out I missed even […]

## How Hamiltonian Monte Carlo works

Marco Inancio posted this one on the Stan users list: ( Statement 1) If the kinetic energy equation comes from a distribution $L$ which is not a symmetric distribution, then thanks to the “Conservation of the Hamiltonian” property we’ll still be able to accept the proposal with probability 1 if we are computing the Hamiltonian’s […]

## New papers on LOO/WAIC and Stan

Aki, Jonah, and I have released the much-discussed paper on LOO and WAIC in Stan: Efficient implementation of leave-one-out cross-validation and WAIC for evaluating fitted Bayesian models. We (that is, Aki) now recommend LOO rather than WAIC, especially now that we have an R function to quickly compute LOO using Pareto smoothed importance sampling. In […]

## An Excel add-in for regression analysis

Bob Nau writes: I know you are not particularly fond of Excel, but you might (I hope) be interested in a free Excel add-in for multivariate data analysis and linear regression that I am distributing here: http://regressit.com. I originally developed it for teaching an advanced MBA elective course on regression and time series analysis at […]

## Short course on Bayesian data analysis and Stan 19-21 July in NYC!

Bob Carpenter, Daniel Lee, and I are giving a 3-day short course in two weeks. Before class everyone should install R, RStudio and RStan on their computers. If problems occur please join the stan-users group and post any questions. It’s important that all participants get Stan running and bring their laptops to the course. Class […]

## Introducing StataStan

Thanks to Robert Grant, we now have a Stata interface! For more details, see: Robert Grant’s Blog: Introducing StataStan Jonah and Ben have already kicked the tires, and it works. We’ll be working on it more as time goes on as part of our Institute of Education Sciences grant (turns out education researchers use […]