Nathan Lambert

Founder, Interconnects AI · 1 appearance on the record.

computed by AI from the episodes · how this works → · full disclaimer →

scientistauthorfounderhostengineer@natolambert ↗LinkedIn ↗interconnects.ai ↗

Nathan Lambert is an AI researcher known for his work in post-training and reinforcement learning from human feedback (RLHF), having played a central role in open-source language model projects including Ai2’s OLMo and Tülu. He writes and hosts the technical publication Interconnects and authored the textbook Reinforcement Learning from Human Feedback.

23statements → 17claims → 5claims resolved → 80%fully supported → 3.7/5average certainty → 2.52/5average debate potential → 4.0/5argument clarity · the sources →

4 supported 1 partly supported 0 contradicted 12 not checkable as stated how the 17 claims stand · each chip opens the sources

3 predictions · 14 assertions · 1 opinion · 1 insight · 3 disclosures · 1 what if · every statement was checked. The predictions and assertions are the 17 claims: statements the public record can support or contradict. 5 are resolved, and 12 name no date, number or outcome precise enough to check. Everything else (opinions, insights, what ifs, disclosures) can never be settled by the record, so it carries no assessment.

The record, in short

What the tape says about how Nathan argues and how the claims held up. Everything they said, and everything said about them, is in the tabs below.

Their most notable supported claim

Assertion Supported
Lambert: OLMo 3 models are the best open models outside Qwen 3
“I would say in post training where The best models that don't start with Quinn three and we're like reasonable to say that they are comparable to Quinn three, like on some benchmarks would beat them on some benchmarks. They're way ahead.”
Nathan Lambert Nov 20, 2025 ▶ 8:59 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"

Expressed certainty vs assessment result

none yet certainty 1
none yet certainty 2
100% certainty 3
88% certainty 4
none yet certainty 5

weighted support: a fully supported claim counts one, a partly supported claim counts half. Each filled bar is clickable and opens exactly those claims; "none yet" means nothing said at that certainty level has resolved yet

Argument clarity: do they answer the question? how? →

4.0 / 5 directness 4.3 · coherence 4 · precision 3.7 · compression 3.3

redirected or did not address 2 of 12 assessed questions (17%). Watch them ▸

This is a score against a rubric. It is not a rank. Every host question → answer exchange is scored with names hidden on directness, coherence, precision and compression, 1–5 each, on meaning alone: disfluencies are ignored, and only raw unedited episodes count. This is the score that measures thought. Every scored exchange, scores shown → · The rubric and its checks →

How they sound: speaking style how? →

265 words/min while actually speaking · 4.1 um and uh per 1k words

Measured by listening to the audio itself: 9,302 words across 1 episode of raw-level tape, transcribed verbatim with every um and uh kept, each one attributed only where the alignment onto our timed stream is unambiguous. These are measurements of speaking style. We do not rank them: across this corpus, fluency and argument quality are nearly uncorrelated (ρ≈0.2), and smooth talking does not signal clear thinking. How it's measured →

Everything Nathan Lambert said on the MAD Podcast that made the record, most notable first. Filter by type, assessment or year in the ledger →

Assertion Not checkable as stated
Lambert: Chinese open AI models currently do not contain backdoors
“Like, you can't prove that the models aren't doing certain backdoors, where I'm fairly certain they definitely aren't now.”
Nathan Lambert Nov 20, 2025 ▶ 17:52 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Prediction Not checkable as stated
Lambert: AI progress will yield steady improvements rather than rapid singularity
“I think these researchers are going to grind out improvements for multiple years, but never in a way that results in this kind of accelerating well that we get drawn into.”
Nathan Lambert Nov 20, 2025 ▶ 1:21:34 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Not checkable as stated
Lambert: OLMo 3 32B base model matches Qwen 2.5 32B quality
“This base model is similar in quality to the best available, which is like Quinn's 2.5, 32 B is, was still the best base model.”
Nathan Lambert Nov 20, 2025 ▶ 4:06 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Not checkable as stated
Lambert: OLMo 3 7B outperforms Meta's Llama 3.1 8B in internal tests
“And I just think of this cause like Lama 3.1 AP is one of the most used models and hugging base of all time. And this should be better. We're, In our measurements, we see it as being better than Llama.”
Nathan Lambert Nov 20, 2025 ▶ 4:54 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Partly supported
Lambert: 80% of a16z's open-model portfolio startups use Alibaba's Qwen
“80% of companies building with open models are using Quinn, which is like 16 to 24% of his portfolio, which is still a lot.”
Nathan Lambert Nov 20, 2025 ▶ 17:01 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Not checkable as stated
Lambert: Chinese companies with $1B+ valuations routinely pirate SaaS software
“Mediumly large, like billion dollar plus valuation companies in China will just like pirate SaaS software.”
Nathan Lambert Nov 20, 2025 ▶ 18:47 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Not checkable as stated
Lambert: Best open-license AI models near the frontier in 2025 were Chinese
“The models that are from closest to the frontier in performance with good license all happened to be Chinese models throughout the year for this case.”
Nathan Lambert Nov 20, 2025 ▶ 58:29 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Prediction Not checkable as stated
Lambert: Big tech will realize 95-98% of LLM potential by 2030
“I think that how I describe it is that big tech has all collectively realized that these language models plus scaffolding is going to unlock absolutely incredible value. And I have very high probability, barring extreme geopolitical situations, that big tech E…”
Nathan Lambert Nov 20, 2025 ▶ 1:24:19 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Not checkable as stated
Lambert: As AI funding grows, fewer researchers speak in public
“There's so much money in AI and it only becomes increasingly so that the amount of people that can talk about these things in public and educate and get more people involved by spreading knowledge is ever smaller.”
Nathan Lambert Nov 20, 2025 ▶ 29:52 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Opinion
Lambert: Rich Sutton's RL theories are impractical for models like GPT-6
“Rich is a font of wonderful ideas, but Often not ones that are going to be immediately practical. This is how you get things like creating reinforcement learning, but not necessarily things that are going to impact what GPT six is.”
Nathan Lambert Nov 20, 2025 ▶ 45:11 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Disclosure
Ai2 fine-tuned OLMo 3 using Chinese teacher models DeepSeek-R1 and Qwen
“So in our case, we took a mix of existing data sets like Open Thoughts three and modified it, which is from Bespoke AI labs, a startup. And then we also generated a whole bunch of new data. So we ended up using a mix of teachers from like Deep Seek R one, oh f…”
Nathan Lambert Nov 20, 2025 ▶ 57:15 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Disclosure
Lambert: Ai2 generated billions of DeepSeek completions over a weekend
“We had a bunch of cloud credits and I, they were running out and we're behind and I just generated like as many completions as possible. So it was like a few billion completions from deep seek over the weekend.”
Nathan Lambert Nov 20, 2025 ▶ 1:08:18 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Insight
Lambert: RLVR targets performance characteristics better than traditional RLHF reward models
“These reward models tend to have a lot of problems and you can over optimize them much more easily because the reward models will pick up on features that are maybe emojis or something like this that you don't actually care about where RLVR is much better matc…”
Nathan Lambert Nov 20, 2025 ▶ 1:13:35 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Supported
Lambert: OLMo 3 models are the best open models outside Qwen 3
“I would say in post training where The best models that don't start with Quinn three and we're like reasonable to say that they are comparable to Quinn three, like on some benchmarks would beat them on some benchmarks. They're way ahead.”
Nathan Lambert Nov 20, 2025 ▶ 8:59 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Supported
Lambert: Alibaba's Qwen 3 VL vision model is a superior text model
“They released these Quinn three VL, their vision models. And like on text only benchmarks, it's way better than the models they released in April. So it's like okay, like that's the new baseline. And most people don't know about it because they think it's just…”
Nathan Lambert Nov 20, 2025 ▶ 9:46 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Prediction Not checkable as stated
Lambert predicts more US labs will release open AI models
“If you look at this podcast in the coming months, I do think there's going to be, look like there's a lot more labs in the U S participating.”
Nathan Lambert Nov 20, 2025 ▶ 16:22 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Disclosure
Lambert: AI2 coined 'reinforcement learning with verifiable rewards' replicating Llama 3
“We spent a long time to try to replicate what we thought was close to Lama three post training with multiple stages and optimizers, which is the project that like came up with the name reinforcement learning with verifiable rewards with a bunch of people.”
Nathan Lambert Nov 20, 2025 ▶ 29:22 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Supported
Lambert: Hugging Face outcompeted AI2's AllenNLP library
“It was the main competitor to Hugging Face Transformers. And they ultimately outcompeted AI two as the thing that people use for that because they had very different model and amount of support.”
Nathan Lambert Nov 20, 2025 ▶ 32:47 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Not checkable as stated
Lambert: Long-context extension is essential for reasoning AI models
“Three is long context extension, which is absolutely essential for these reasoning models because they generate so many intermediate tokens before sharing an answer with you.”
Nathan Lambert Nov 20, 2025 ▶ 40:15 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
What-if
Lambert: Scaling AI 10x alters post-training, not pre-training methods
“If like, if we were to train a model that was 10 times as big, like all this post-training stuff would change. But the pre-training And mid training and long contacts, I think would actually become looking pretty similar.”
Nathan Lambert Nov 20, 2025 ▶ 40:55 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Not checkable as stated
Lambert: Larger pre-trained base models are easier to improve with RL
“A better base model and a bigger base model is much easier to improve with RL.”
Nathan Lambert Nov 20, 2025 ▶ 44:29 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Supported
Lambert: Kernel differences between vLLM and Hugging Face cause RL numerical instability
“VLLM and HuggingFace use different kernels to do the actual internal computation of the model. So these kernels are the things that make things like vLLM really fast. But these things, this then results in subtle numerical differences between the completions t…”
Nathan Lambert Nov 20, 2025 ▶ 1:15:29 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"
Assertion Not checkable as stated
Lambert: Most AI labs probably use evolved GRPO rather than PPO
“In reality, it seems like most people are using something like an evolved version of GRPO, which is a bit simpler than PPO.”
Nathan Lambert Nov 20, 2025 ▶ 1:16:39 Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking"

Appearances (1)

EpisodeDateSpeaking time
Open Source AI Strikes Back — Inside Ai2’s OLMo 3 ‘Thinking" Nov 20, 2025 42m
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