Pelayo Arbués

Wow! 2000 followers! Let me reintroduce myself: I’m Head of Data Science at idealista.com, Southern Europe’s leading real estate portal. I earned a Ph.D. and spent 7 years in academia researching transport and spatial econometrics. I’m into AI, management, and film photography.👇👇👇

A group of 25 Fields Medalists, including myself, have made a joint declaration on Math and AI: mathandai.org . We welcome additional signatories. See also this article in the Economist announcing the declaration: www.economist.com/science-and-...

Abrimos posición en el equipo de datos de idealista/data! Un rol muy de remangarse, hacer nuevas versiones de productos de datos existentes, trabajar con el equipo de negocio, ayudar a migrar a nuevo stack y mucho ELT. www.linkedin.com/jobs/view/44...

what’s your favorite way to have your data? data base data center data mart data warehouse data lake data stream data pipeline data mesh data fabric data swamp data silo data cube data frame data vault data catalog data platform data store data pipe data table data feed data channel data bus

Save your data to local Markdown files you own forever, and can access completely offline. Obsidian now helps you migrate from all the major proprietary formats including Notion, Evernote, OneNote, Google Keep, Apple Notes, and more.

So we know AI helped a negligible number of students. But how many did it harm? I've crunched the raw data provided by the lead researcher, and what I've found is that ~9,500 students using AI studied less than even the *least* studious, non-AI using student. This should shock the conscience.

We lost reading. www.pelayoarbues.com/notes/we-los...

Autonomous AI in action. 🤖 Check out how the new Gemma 4 31B model operates as an ADK Agent, exploring, planning, and running experiments on an unfamiliar database to optimize services and maximize revenue. 📈 ✨ Dive into the full session here to explore the complete workflow: goo.gle/4ozP8sK

When people say 'AI isn't a bubble because the technology isn't going away', it just shows they don't know what a bubble is. The internet didn't go away. Railways didn't go away. Tulips didn't go away. An asset can be overvalued, even if its useful.

Mamá salgo en @forbes.com! Podeis escuchar/ver el podcast con la entrevista que me hicieron en Open C. forbes.es/brandvoice/9...

I have been working on Obsidian Reader for over a year. I didn't want to share it until I felt it was good enough. It's finally there. Consistent formatting for any article. Outline, syntax highlighting, nice footnotes, adjustable typography. Runs locally. Just rules, no AI.

When you search for a home, it’s rarely “the whole city.” It’s more like: this neighborhood yes, this one no, that other one too, even if it’s far away. With @idealista.bsky.social new multi-area search, you can mix, exclude and add zones in one map search.

I am calling for a complete and total boycott of the Mercator projection in all news stories about Greenland until every member of the American public has seen this

The books I read in 2025. I followed the same habit that worked so well in 2024: reading non-fiction first to satisfy my curiosity and then switching to fiction to wind down. This routine is still the best compromise I’ve found between learning and resting. www.pelayoarbues.com/notes/Wrappe...

I declare myself allergic to self-proclaimed experts. www.pelayoarbues.com/notes/Self-p...

Once again I really, really needed this for a better Friday! It is more relevant and hilarious every time I visit. alignmentalignment.ai

Just finished reading 3 Millones de Viviendas by @jorgegalindo.bsky.social. One of the sharpest takes on Spain’s housing crisis I’ve seen. Data, history, and a tough question: what kind of country do we want to build? www.pelayoarbues.com/notes/Tres-M... #realestate

I'm ready to accept a definition of "agent" that I think is widely-enough agreed upon to be useful, at least in the AI engineering space: An LLM agent runs tools in a loop to achieve a goal (I've been dismissing the term as hopelessly ambiguous for years) simonwillison.net/2025/Sep/18/...

Context engineering is the new AI buzzword. And here we go again: www.pelayoarbues.com/notes/Contex...

The data industry promotes builders. Not leaders. You nailed pipelines. So they gave you politics. Now you're managing people, budgets, and roadmaps. With zero training. You’re not unqualified. You’re just undertrained.

OpenAI announced Codex (openai.com/index/introd...) on May 16, 2025 for their $200/month Pro users, and Google announced a competing tool called Jules (jules.google) on May 20, 2025 making it available for FREE. There’s no moat in AI—how can a moat disappear in less than a week?

Veo 3: "a big broadway musical about garlic bread, with elaborate costumes and a sondheim-like vibe"

Every AI coding tools company doing demos with React + Typescript (and maybe React Native.) Microsoft meanwhile showing off Java and .NET case studies. This doesn’t look like an accident - but a very deliberate strategy. It’s easier to win when you are on a ground with fewer competitors…

500 days reviewing highlights on @readwise.bsky.social!!!

I just shared a learning path guide for software developers looking to infuse AI into their products, tailored specifically to your needs, interests, and how deep you'd like to dive. www.pelayoarbues.com/notes/AI-Lea...

When people are pressured to meet a target value there are three ways they can proceed: 1) They can work to improve the system 2) They can distort the system 3) Or they can distort the data — Donald Wheeler commoncog.com/goodharts-la...

I don't know why people think picking a model on ChatGPT is so complicated.

SmolVLM real-time camera is a framework for running computer vision models locally on M3 MacBooks. It combines HTML webcam access with llama.cpp's inference process to enable real-time image capture, understanding, and captioning. www.threads.com/@luokai/post...

It is a little weird to me countries aren’t more aggressively, formally trying to take advantage of the U.S. science brain drain. Once in a lifetime opportunity to buy low on Non-Dumbass Americans with PhDs who just wanna look into microscopes and quietly cure ass cancer as our country eats shit.

Nuevo post. Área de aplicación. Cosas curiosas que he leído este finde y que me parecen interesantes. Reproduzco parte de un post de Jakub Nowosad muestrear-no-es-pecado.es/2025/05/aoa

Just finished 'Power and Prediction'. Loved the economic take: AI dramatically reduces prediction costs but leaves human judgment scarce. Also, great analogy with electricity, real AI impact requires systemic change www.pelayoarbues.com/notes/Power-...

Spain's power is slowly coming back, but situation still far from normal. Out of the 33 GW scheduled for this evening peak, only 18 GW is available. Nuclear and coal-fired power plants still offline.

When we don’t know someone well, we tend to project intentions onto them, casting them as a character in a play they themselves are unaware exists.

Why software engineers should learn a bit of data science www.pelayoarbues.com/notes/Why-So... #databs

In simple terms, the purpose of data is to give you a causal model of your business in your head. If reality changes, the figures in your business should show it. At which point you get to update your knowledge.

Coaching is no longer a specialty; you cannot be a good manager without being a good coach. The path to success in a fast- moving, highly competitive, technology- driven business world is to form high- performing teams and give them the resources and freedom to do great things.

When leaders take steps to protect their own interests, particularly when those steps are taken at the expense of others, they send a message to everyone else that it is okay to do the same.

To maintain the core of your product there are usually one or two things that have to stay still while everything else spins and changes around them. And that’s a useful constraint. You need some constraints to force you to dig deep and get creative.

Yes, leadership is about vision. But leadership is equally about creating a climate where the truth is heard and the brutal facts confronted

If people only comply, we can’t expect people to take responsibility for their actions. The chain of command is for orders, not information. Responsibility is not doing as we are told, that’s obedience. Responsibility is doing what is right.

The push for commercial control of AI capability is dangerous. Naomi Klein, who coined the term “shock doctrine” as “the brutal tactic of using the public’s disorientation following a collective shock… to push through radical pro-corporate measures”

What AI person is saying..... Anthropic CEO, Dario Amodei: In the next 3 to 6 months, AI is writing 90% of the code, and in 12 months, nearly all code may be generated by AI. What AI person is doing..... www.anthropic.com/jobs

Having two different pipelines to process your data is a common cause for bugs in ML production. One cause for bugs is when the changes in one pipeline aren’t correctly replicated in the other, leading to two pipelines extracting two different sets of features.

Every three to six months, audit your meetings. Are they useful? Are the right people involved? Do they achieve their purpose, and are they worth the time? Could more be accomplished asynchronously? Consider polling participants or having a neutral person do so.

Not finance. Not strategy. Not technology. It is teamwork that remains the ultimate competitive advantage, both because it is so powerful and so rare.

Make sure your candidates know that you’re excited about them. I first encountered this idea reading Rands’s “Wanted” article, 4 and he does an excellent job of covering it there. The remarkable thing is how few companies and teams do this intentionally.

Self-awareness has three components: understanding your underlying value system, identifying your innate preferences—your work style and decision-making tendencies—and being clear about your own skills and capability gaps.

To write something, you have to do things, collect ideas, process them, put words on the page, structure them, edit them, rewrite them, and publish them to your site — and that’s all for one article. Then, there’s the emotional challenges: writer’s block, imposter syndrome (...)