Latest: Episode 30

Smuggled Gold and Untrustworthy Intuition — with Leland McInnes

Leland McInnes has spent his career building tools a lot data scientists take for granted (UMAP, HDBSCAN), and amusingly the applications keep getting stranger. On this episode of The Test Set, he tells Michael, Hadley, and Wes about teams tracking laundered gold through mineral impurities, and the time he helped casinos optimize slot machine layouts. Also, why nobody's intuition survives contact with high-dimensional space. On this episode of The Test Set, we hit all that, plus imposter syndrome, AI as a sounding board, and the case for asking better questions instead of chasing answers.

View episode details
Recent Episodes
Trevor Manz
Episode 28

Let the Agent Cook — with Trevor Manz

Trevor Manz went from measuring plant apertures by hand in a wet lab to building the notebook that lets coding agents take the wheel. The creator of anywidget and founding engineer at marimo (marimo.io/pair) popped into The Test Set to spill on reactive notebooks, why marimo pair threw out every MCP tool but one, and what agents really want out of a data environment. This conversation also features a jacket bouncer, a hidden Python API, and Michael's slow-motion war with the word "marimo."

Release date: 11 August 2026
View episode
Leilani Battle
Episode 27

The Answer Was Never Us — with Leilani Battle

Leilani Battle studies how software quietly shapes what we see and believe. The University of Washington professor and co-director of the UW Interactive Data Lab talks with Michael, Hadley, and Wes about an experiment that manipulated people using nothing but loading speed, and why AI models don't seem to recommend charts the way the community that studies charts actually does. Other highlights: rationality's blind spots and a thorough disc golf origin story.

Release date: 28 July 2026
View episode
See all podcasts
Data Scientist and Software Engineer at Posit, PBC

Michael Chow

Michael is a data science tool builder at Posit, where he works on open source tools for data analysis. He received a Ph.D. in Cognitive Psychology from Princeton University, and is interested in what drives expert data science performance. When not wrangling data, you can find him in Philly writing tiny poems, baking bread, and embroidering.
Hadley Wickham Headshot
Chief Scientist, Posit

Hadley Wickham

Hadley is Chief Scientist at Posit PBC, winner of the 2019 COPSS award, and a member of the R Foundation. He builds tools (both computational and cognitive) to make data science easier, faster, and more fun. His work includes packages for data science (like the tidyverse, which includes ggplot2, dplyr, and tidyr)and principled software development (e.g. roxygen2, testthat, and pkgdown). He is also a writer, educator, and speaker promoting the use of R for data science.
Wes McKinney Headshot
Principal Architect, Posit

Wes McKinney

Wes McKinney is Principal Architect at Posit and an open source software developer focusing on analytical computing. He created the Python pandas project and is a co-creator of Apache Arrow, his current focus. He authored two editions of the reference book, Python for Data Analysis.