The Test Set by Posit

Posit, PBC

A Posit podcast for data science junkies, anomaly hunters, and those who play outside the confidence interval. Hosted by Michael Chow, with co-hosts Wes McKinney & Hadley Wickham.

  1. 6 days ago

    The Code Doesn't Lie — with Mike Bostock

    Mike Bostock made D3 when the browser was still a joke. He built bl.ocks when people needed somewhere to share their work. Now he's building Observable — reactive notebooks with an AI that actually looks at what it made. In this episode: the three-GIF bar chart that launched 25 years of viz, why open source needs both intrinsic and extrinsic motivation, and why an agent that can't see its own output is likely to be confidently wrong. What's Inside The 1998 visualization library that could only make bar chartsWhy D3 hit #3 on GitHub, and what killed the galleryWhat spreadsheets got right that notebooks ignored for years"The agent can lie with text, but not with code"Why Observable scrapped canvases and went back to notebooksThe penguin dataset that exposes AIStrength training, tennis mind games, and a resurrected Stanford game

    1hr 8min

  2. 18 May

    The Wonder-Driven Builder — with Paige Bailey

    Paige Bailey is a developer relations engineering lead at Google DeepMind. She's a geophysicist-turned-AI-engineer who was once told by her professors that building open-source libraries was a waste of time. We talk about her path from planetary science to TensorFlow, why statisticians have a hidden edge in the age of AI, and what it means to be a curious generalist when the cost of building software is approaching zero. Bonus: installing solar-powered silent-film birdhouses as street art in San Francisco. What's inside From planetary science to TensorFlow, before it was GPU-capableGeophysicists as early GPU adoptersThe professors who said open-source wasn’t “real science”Building silent-film birdhouses as San Francisco street artHiding Gemini API tests inside whimsical side projectsThe right-tool-for-the-job case for mixing AI modelsWhy “taste” is the skill that matters when code costs nothing

    46 min

  3. 4 May

    Widgets Are Lego Bricks (and Other Things People Are Sleeping On) — with Vincent Warmerdam

    Vincent Warmerdam has been the first full-time hire at a startup, a spacey punster who accidentally got himself a job, a bartender at an Amsterdam comedy theater, and a Dutch bike tour guide — and he'll tell you all of it was career development. Now doing DevRel at Marimo, Vincent makes the case for reactive notebooks, Lego-brick widgets, and why "number go up" is not a data science strategy. Also: chickens die. The model doesn't know. This matters more than you think. What's inside How a spacey pun accidentally launched Vincent's careerWhy Marimo's constraints make it better for LLMs, not just humansThe gorilla hiding in your dataset — and why the model missed itVibe coding vs. notebooks: three cells at a time as a disciplineWidgets as Lego bricks: reusable, composable, criminally underusedCognitive debt, confirmation bias, and sycophantic data scienceWhy natural intelligence is still, actually, a pretty good idea

    1hr 16min

  4. 20 Apr

    Everything's a Fad (Including This Podcast) — with Benn Stancil

    Benn Stancil built Mode Analytics, spent a decade in the data trenches, and now writes some of the sharpest, funniest essays in the data world. On The Test Set, he talks about the cultural shift from Nate Silver to Rick Rubin why AI might kill the analytics dashboard, and what happens when a thousand startups all build the same thing. Plus: boy bands as a model for collaboration, and why the best creative work starts with cheating. What's inside:  Why the modern data stack was basically big data 2.0The cultural flip from Nate Silver to Rick RubinGas Town, tar pits, and the AI startup zero-sum gameSoftware is becoming content, and that changes thingsBenn's creative process: Lorde lyrics, Codenames, and cheatingThe boy band as a model for small-team collaborationBI is (mostly) dead, and vibes might replace SQL

    1hr 35min

  5. 6 Apr

    Deeply Unsexy: SQL's Redemption Arc — with Tristan Handy

    dbt Labs CEO Tristan Handy drops into The Test Set to map the fault lines between the data science world and the enterprise data world — and explain why analytics engineers are basically pissed-off data analysts who decided to organize the bookshelf. We get into SQL's glow-up, the community magic of dbt Slack, what AI agents mean for data warehouses, and why everyone's building iOS apps with Claude now. What's inside: What analytics engineers *actually* doSQL's journey from deeply unsexy to indispensableHow dbt turned source control into a source of truthBuilding a tech community without the RTFM energyAI agents on your data lake: permissions get personalWill LLMs kill the open-source package ecosystem?Edible gardening, welding dreams, and digital dysphoria

    1hr 6min

  6. 23 Mar

    Your VP Is Doing a Rogue Analysis in Cursor Right Now — with Nell Thomas

    Nell Thomas has spent two decades in data — from equity research to the DNC to Facebook to leading a 400-person data org at Shopify. She walks Michael and Wes through the modern data stack role by role, gets honest about what AI is and isn't changing about data work, and admits the semantic layer has been her greatest leadership failure. Plus: Sneakers gets the respect it deserves. Episode Notes What does it actually look like to run data infrastructure for millions of merchants while the entire industry reinvents itself in real time? Nell Thomas (VP of Data, Shopify) talks vibe-coded dashboards, political campaign data scarcity, blameless postmortems, and why no one should be locking in on an AI strategy just yet. Recorded live in Times Square. What’s Inside Mapping the modern data stack, role by roleWhy data quality is still the #1 problemWhat "good scrutiny" looks like on a data teamVibe coded dashboards and the trust problemShopify's MCP for their data warehouseThe throwaway tech problem in political campaignsWhy the semantic layer is so damn hardSneakers!

    1hr 23min

  7. 9 Mar

    Sleeping Rats and Sociopathic Agents — with Phillip Cloud

    Phillip Cloud has been shaping the Python data ecosystem since the early pandas days — and he has *opinions*. Now a principal engineer at NVIDIA leading the Ibis project, Phillip talks about how he stumbled into open source via an eye movement lab, why he prefers his coding agents cold and emotionless, and what happens when you ask an LLM for woodworking trig. Plus: terminal user interfaces, the file hierarchy standard hot take nobody asked for, and the pineapple-on-pizza hill he's willing to die on. Episode Notes Phillip Cloud (NVIDIA, Ibis project) joins Michael Chow, Wes McKinney, and Hadley Wickham to talk about his path from eye movement labs to pandas core team, why developer productivity tools have quietly gotten amazing, his brutally honest take on coding agents, and what it would actually take to impress him. Also: VisiData love, NixOS evangelism, and yard work as therapy. What’s Inside From eye movement labs and MATLAB to pandas core teamColumn multi-indexes: the feature nobody likes but Phillip neededWhy your command line tool better have a sweet TUIVisiData: the terminal data tool you're sleeping onAre we writing code for humans or for agents now?Phillip's AI skepticism journey: Cursor, Claude Code, and frustrationThe Numba CUDA test suite port that would finally impress him

    56 min

  8. 23 Feb

    More productive but a lot less fun — with Charlie Marsh

    Charlie Marsh built Ruff, uv, and Ty — the tools that mass-fixed Python's worst pain points. Now he's grappling with what happens when agents start writing most of the code. In this episode, Charlie gets real about his team trusting his PRs less, the gnarly middle of coding with agents, and whether Python is even the right language for an agentic future. It's honest, a wee existential, and deeply relatable if you ship code for a living. Episode Notes Charlie Marsh is the founder and CEO of Astral — the company behind Ruff, uv, and Ty. He sits down with Michael and Wes to talk about what it's actually like building with coding agents every day, why his team's code review dynamics completely changed, and big open questions about code quality, open source community, and Python's future nobody has answers to yet. What’s Inside How Ruff convinced mass adoption when switching tools is painfulWhy "just uv run it" became the killer featureHiring outside Python's ecosystem to build tools for itHis team said "we trust your PRs less now"Engineers screen-sharing their actual agent workflows at AstralThe "Lisp Curse" reborn: cheap code breaking open sourceIs Python the wrong language for an agentic world?

    1hr 35min
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About

A Posit podcast for data science junkies, anomaly hunters, and those who play outside the confidence interval. Hosted by Michael Chow, with co-hosts Wes McKinney & Hadley Wickham.

Information

  • Creator
    Posit, PBC
  • Years Active
    2025 - 2026
  • Episodes
    23
  • Rating
    Clean
  • Copyright
    © 2026 The Test Set by Posit
  • Show Website
    The Test Set by Posit

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