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Going In Deep On Data | YC Paper Club Transcript, AI Summary & Key Points

Y Combinator · 2 hours ago · Science & Technology · 52:35 · EN-US

🧠 AI Summary

Data, rather than model architecture or compute hardware, is presented as the central bottleneck for deploying capable AI systems. High-quality data requires expert judgment, careful curation, realistic environments, verifiable rewards, and benchmarks that reflect real-world complexity. Vincent Sunn Chen explains how expert supervision can be encoded in software and scaled through validation agents and benchmark design. Volo Kuleshov presents diffusion language models, which generate tokens in parallel and can exceed 1,000 tokens per second, along with Data Forge for synthesizing realistic reinforcement-learning environments from real-world usage. Shayne Longpre presents ATLAS, a framework for understanding multilingual data synergies, interference, scaling laws, and the data and model-size requirements for different language targets.

🔑 Key Points

  • After a model reaches a reasonable performance level, inspecting the data, especially false positives and false negatives, is more valuable than immediately changing the architecture.
  • Production data differs from clean training data, creating distribution-shift failures when models encounter cases absent from the training distribution.
  • Training useful AI systems for domains such as medicine, law, accounting, trading, and therapy requires current, curated expert data and reinforcement-learning environments.
  • Data sets and environments are products that require substantial craftsmanship, including decisions about edge cases, ontologies, verifiers, and changing interfaces.
  • Data can remain a bottleneck even when a company has captured a very large amount of usage data, because products and user interfaces change over time.
  • Expert supervision is the process of transferring expert judgment from people's heads, messy documents, and knowledge corpora into data usable for training and evaluation.
  • Manual labeling is difficult to scale, is vulnerable to noise, must often be repeated when specifications change, and does not preserve the rationale or provenance behind labels.
  • Snorkel's data-programming approach encodes expert supervision as software, allowing it to be scaled, adapted, audited, and collaboratively reviewed.
  • Weak supervision combines overlapping and imperfect labeling signals, estimates their quality without ground-truth labels, and uses noise-aware models to extend coverage.
  • As agents become more autonomous and operate in more complex environments, benchmark and training-data challenges become more difficult rather than becoming saturated.
  • Senior SWE-Bench was designed to evaluate coding agents on work more representative of senior-engineer responsibilities, using higher-level instructions, realistic environments, and nuanced rewards.
  • Pre-written verifiers offer high reliability but limited flexibility, while LLM judges offer flexibility but can produce false positives and overreward plausible but incorrect solutions.
  • A validation agent can translate expert-written user stories and requirements into deterministic tests that exercise the relevant code paths.
  • The Senior SWE-Bench work introduced a tasteful-pass metric that combines correctness with code-quality considerations such as engineering judgment and minimizing patch bloat.
  • More benchmarks are needed to drive research into data for increasingly complex agents.
  • Diffusion language models generate tokens in parallel through multiple refinement steps instead of generating them sequentially from left to right.
  • Diffusion language models can reach speeds above 1,000 tokens per second, making them useful for latency-sensitive applications such as real-time voice agents.
  • Benchmark performance can substantially exceed production performance when benchmarks have fewer specifications and tools or become heavily optimized against.
  • Data Forge synthesizes realistic reinforcement-learning environments, tasks, simulated users, and tools using real user interactions, provider data, production partnerships, or information from a business knowledge graph.
  • Synthetic tasks must be neither too easy nor too difficult; filtering and hardening procedures are used to maintain useful learning signals.
  • Training Mercury 2.5 on an initial set of tasks synthesized by Data Forge improved performance on another set of environments by over 23% from an initial accuracy of about 50%.
  • In multilingual pre-training, languages can have positive synergies or negative interference, and these relationships must be measured empirically rather than inferred only from language families.
  • In Madlad 400, Thai has 0.6% of the number of tokens available in English, creating severe data constraints for Thai-language modeling.
  • A monolingual model can overfit when the available data for a lower-resource language is repeated too many times.
  • The usefulness of one language for another is directional rather than necessarily symmetric.
  • Shared script and shared language family both affect transfer between languages, but shared script mattered somewhat more in the experiments described.
  • Larger language models can accommodate more languages and turn some interference relationships into synergies, while smaller models experience more competition for representational capacity.
  • Multilingual scaling laws can model target-language data, transfer-language data, other data, and diminishing returns to predict loss and guide mixture and model-size decisions.

✅ Actionable items

  • When a model underperforms, inspect false positives and false negatives, group them into recurring issue buckets, and address the largest bucket first.
  • Inspect production examples to identify cases missing from the training distribution.
  • Treat training data, evaluation data, and reinforcement-learning environments as engineered products that require explicit handling of edge cases.
  • Update data when the product interface or operating environment changes.
  • Encode expert judgment in software so it can be scaled, refactored, audited, and reviewed.
  • Use overlapping supervision sources and noise-aware modeling when ground-truth labels are unavailable.
  • Design benchmarks around realistic tasks, higher-level instructions, relevant environments, and nuanced success criteria.
  • Balance deterministic verifiers with flexible evaluation methods, using validation agents to generate tests from expert specifications.
  • Calibrate evaluation procedures against senior engineers and use checks for fidelity, completeness, collusion, and reward hacking.
  • Continuously compare synthetic environments and model results with real-world data and user feedback.
  • Filter or harden generated tasks so they provide a useful learning signal without being trivial or impossible.
  • Measure transfer between language or data sources empirically, including direction-specific effects, instead of assuming that related sources transfer equally well.
  • Account for diminishing returns when repeatedly using limited data during pre-training.

💡 Business ideas

Domain-specific expert data and reinforcement-learning environment company02:23

Build curated training data, evaluation datasets, and verifiable reinforcement-learning environments for a specific expert domain, using practitioners' judgment rather than treating datasets as generic files.

For
AI companies and enterprises building agents for domains such as medicine, accounting, law, trading, customer support, or software engineering.
Solves
General-purpose models fail when production data differs from training data, when interfaces change, or when domain-specific judgments and preferences are absent. Manual expert labeling is expensive, difficult to scale, vulnerable to noise, and often lacks provenance.
  • Focal's in-stock/out-of-stock computer-vision system used error buckets to identify failures caused by fogged refrigerator glass, people blocking the view, and other scene conditions.
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Ultra-fast diffusion language model service for latency-sensitive agents02:52

Build language models that generate an initial noisy sequence and refine multiple tokens in parallel, targeting real-time voice and other applications where autoregressive latency limits the user experience.

For
Companies deploying latency-sensitive voice agents in customer support or education, as well as companies building search and code applications.
Solves
In cascaded voice systems, the central language model can bottleneck overall latency. Faster inference can make conversations more seamless, allow deployment of a larger model, or permit longer reasoning.
  • Mercury 2 was reported to reach speeds over 1,000 tokens per second and to provide a quality-latency frontier on voice benchmarks.
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Multilingual pre-training mixture and scaling optimization service04:05

Help AI developers choose multilingual training-data mixtures and model sizes by empirically measuring transfer, synergy, and interference between language or other data sources.

For
AI developers building models for underrepresented languages, cultures, societies, or domains with uneven data availability.
Solves
Low-resource languages have far fewer training tokens than English, while monolingual training can repeatedly reuse scarce data and overfit. Adding other languages can help or hurt, and the relationship is not reliably determined by language family or intuition alone.
  • Thai had about 0.6% as many tokens as English in Madlad 400, illustrating the data constraint for a lower-resource language.
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🤖 AI in practice

Used for

Improve a trained model by inspecting false positives and false negatives, grouping the errors into buckets, and addressing the largest data-related issue. 01:23
Encode expert judgment as programmatic labeling logic so large datasets can be labeled, denoised, adapted, and audited. 10:07
Build a benchmark that evaluates coding agents on realistic senior-engineering work rather than narrowly specified junior-level coding tasks. 18:30
Evaluate generated code against expert-defined requirements while allowing different valid implementations. 23:03
Generate diffusion language model outputs for latency-sensitive real-time voice interactions. 28:43
Synthesize realistic reinforcement-learning environments for training and evaluating models in production-like domains. 33:28
Improve a language model on diverse business domains using synthetic tasks generated from production-like environments. 03:48
Choose multilingual pre-training data mixtures and model sizes by measuring how different language sources transfer to or interfere with a target language. 45:05

Agents

  • validation agent — Turn expert-written user stories and requirements into tests that evaluate patches generated by coding agents. 2 held 23:03
  • Dowo Forge — Generate realistic synthetic RL environments and tasks for model training and evaluation. 2 held 33:28

Advice

  • After a model reaches an initial performance level, inspect and bucket its false positives and false negatives before changing the architecture. for A machine-learning developer
    The largest error category often reflects a data or coverage problem that more layers will not fix.
  • Treat expert datasets and RL environments as carefully crafted products, not interchangeable ZIP files. for A founder or team building AI data products
    Correct ontologies, comprehensive coverage, realistic environments, verifiable rewards, and preference data require substantial craftsmanship.
  • Use current, curated expert data and expert RL environments when building domain-specific AI systems. for A founder building a domain-specific AI system
    An AI doctor, accountant, lawyer, trader, or therapist needs domain expertise, up-to-date data, and environments that reflect the target work.
  • Design benchmarks around realistic tasks, environments, and nuanced evaluation criteria as agent capability and autonomy increase. for A benchmark researcher or AI evaluation team
    Simple evaluations can saturate while agents still fail on complex, long-running, environment-dependent work.
  • Use deterministic execution-based checks together with flexible model-based judgment rather than relying exclusively on either one. for An AI evaluation engineer
    Fixed verifiers can produce false negatives for valid implementations, while LLM judges can overreward plausible but incorrect solutions.
  • Continuously compare synthetic training and evaluation environments with real production logs and user feedback. for A team generating synthetic RL data
    This helps update the harness and synthetic-generation process so the environments remain representative of deployment.
  • For multilingual pre-training, empirically measure transfer between each source language and the target instead of assuming transfer is symmetric or determined only by language family. for A multilingual-model developer
    Transfer can be asymmetric, and script similarity, tokenization, data quality, and topical overlap can matter; script was found to matter somewhat more than language family.
  • Fit multilingual scaling laws that account for every data source, diminishing returns, and the target language before selecting the mixture and model size. for A pre-training researcher or model-training team
    A one-dimensional scaling law based only on total data cannot explain how additional languages affect performance on a specific target.

What it could not do

  • Models can fail when production inputs contain examples outside the training distribution. — A model may perform well on a clean training set but fail when launched into production and exposed to unseen test-distribution points.
  • Manual labeling does not scale well, is sensitive to noise and specification changes, and lacks provenance about the rationale behind labels. — Reducing noise requires redundant relabeling, while changes to the task definition or schema can require starting over; niche expert domains can make large-scale labeling fundamentally intractable.
  • Existing coding benchmarks can evaluate advanced coding agents as if they were junior engineers. — Traditional tasks may be overly specified and fail to represent architectural decisions, broad refactoring, and other work expected from senior engineers.
  • Pre-written deterministic verifiers can penalize valid solutions that differ from the expected implementation shape. — They are reliable because they execute against the code, but their low flexibility can create false negatives.
  • LLM judges can be unreliable when evaluating generated code. — They are flexible across solution shapes but may fail to exercise the code path and overreward plausible yet incorrect solutions.
  • Common voice-agent benchmarks may not reflect real-world complexity and can be heavily benchmarked. — The benchmark environment described has roughly an order of magnitude fewer specifications and fewer tools than real customer-support settings; models scoring in the 90s on the benchmark can score much lower on production logs, with greater variation across model sizes.
  • Synthetic task generation must avoid tasks that are either too easy or too hard. — Tasks that models consistently solve provide little learning value, while tasks that are too difficult provide insufficient learning signal.
  • Low-resource languages can have insufficient pre-training data, causing repeated epochs, overfitting, and weaker performance. — Madlad 400 contains 0.6% as many Thai tokens as English, and monolingual training on the limited Thai data repeats it excessively.
  • Adding languages to a model can cause interference, especially when the model is small. — Languages compete for tokens or representational capacity; many transfer relationships become more synergistic as model size increases, while smaller models show more interference.

🧰 Tools & AI usage

  • Snorkel — Encodes expert supervision as labeling functions and combines noisy supervision sources for scalable data labeling.10:05
  • Docker — Packages agent tasks, rubrics, verifiers, and executable reinforcement-learning environments.12:12
  • Harbor — Provides the evaluation framework referenced for coding-agent tasks.19:30
  • SWE-bench — Serves as the original coding benchmark that Senior SWE-bench extends toward senior-engineer-level work.18:47
  • TForge — Orchestrates agents to synthesize realistic reinforcement-learning environments and tasks from domain descriptions, real usage data, scenarios, and personas.33:27
  • Mercury 2 — Provides diffusion-language-model inference for high-speed voice and other latency-sensitive applications.30:27
  • Google TPUs — Provided the compute used for the multilingual pre-training experiments.40:32
  • Madlad 400 — Supplied the multilingual pre-training corpus used to compare language data availability.43:00

AI is used for

  • Image classification — Determine whether products are in stock or out of stock in production environments.01:22
  • Agent evaluation — Measure the correctness, reliability, flexibility, and engineering quality of coding agents.17:58
  • Real-time voice interaction — Power voice agents for customer support and education with lower latency.29:59
  • Customer-support automation — Assist users in realistic business environments using tools, policies, databases, and simulated tasks.34:34
  • Multilingual language modeling — Predict performance and select data mixtures and model sizes for target languages.41:08

📄 Transcript

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00:00 [music] Welcome to YC data club this time. I hope you guys like the little picture that we have this time. Paul Graham didn't like that I was slacking off in my little crown over there, but he does know know my name now, so that's good. All right, so why data? Why does it why does data warrant uh its own night to talk about? Um, in 2016 I left my PhD program and I started focal systems.

00:29 And back then the notion was that data is commodity. I already have downloaded imageet. How much more data do I possibly need? And there was lots of chatter about scale being worth a billion dollars. There's no chance. And there was a lot of VCs except who was the guy that did scale series A? I think it was Levy at Excel. Um, besides him, everyone said the terminal value of data businesses was zero dollars.

00:54 And since then, I think it's like a hundred billion dollars in market cap creation. So, rest assured, the entire VC uh community has changed their tune on that. And why? Well, the interview question I would typically ask at Focal, I still ran the deep learning team uh even until I left for nine years later was um you know, let's say I had to interview these PhDs uh from Stanford or MIT, super smart people, and I would say okay, you have you trained your model, you're at 85% F1 score on hot dog, not hot dog.

01:28 What do you do next? And if your answer was, oh, I would go read some papers. I would like try Reu versus Gellu. I would like add more layers. I do like nope. Next. Literally no. No. No. No. No. And the reason why is because you have to look at the data. The correct answer is you look at the data. You classifi look at all the false positives. You look at all the false negatives.

01:49 You put them in purto buckets. You say, "What's the biggest issue?" And for us, for in stock, out of stock, it's like, "Okay, it's when the fridge has some fog on it. We can't see through the fog or when there's a person in the way or when something else is happening." like the the number of layers didn't was not going to change if there's a person in the way and you can't possibly tell if there's an in stock or out of stock.

02:09 And so it's just looking at data and Andre I would say was the most on this um and he famously did the first measurement of what human level is on ImageNet and where he actually looked through and tried to see how good he could be. And we're not that good. I can't tell the difference between Eskimo sheep dog and uh Siberian husky. I'm not that I'm I'm not good at that.

02:31 And like 30 40% of imageet is dogs are types of dogs. And like people kind of don't know that stuff. And so the data that you're training on ends up being in much more important than the architecture itself especially when the architecture is very expressive. And so in your PhD he says he spent maybe uh 5% of his time thinking about data um and 95% of his times focus on the architecture.

02:55 And then when you go into production that flips and I would say he was saying 25 74% I think nowadays it's like 3% 97%. And it's really about the data now that we have the transformer uh and it works really well. And so and why is this why does the data matter so much? It's because in your nice little imageet train set everything is really nice. The train distribution is beautiful.

03:17 It's amazing. And then when you launch it into production which raise your hand if you've ever had this experience. that happens and then you start getting a bunch of points in in in the in the test distribution that you didn't have in the train and the model you know pukes itself and can't it doesn't work. So to automate the economy if this is the GDP val uh we need both expert data and expert RL environments RL environments for the verifiable uh rewards and then for the pref style data like very subjective do I do

03:53 you like this design do you not like this design is this more usable or less usable you you may the code may work but the coding style is awful and it's unmaintainable code for things like medical like two doctors don't agree on the answer for a given patient and and same thing with judges. Um and so these are preference style answers and that runs a lot of the economy and the right way to think about data sets and our environments for sure is these are products.

04:20 If you talk to Greg at ArcGI, the amount of craftsmanship that goes into each game that Prime Intellect just crushed um to be fair is incredible. It's very very difficult to make these data sets really really good fully comprehensive and even for focal such a simple thing of like in stock and out of stock the amount of time that was spent and how do we handle product pushers like it looks like a product um but it's just pushing product to to the front and so how do should should we have that be a separate uh uh class

04:51 in the ontology or should we classify that as an out of stock because it technically is an out of stock but it's going to confuse the model because an out of stock and a product look very Um, so how do you handle all this stuff? It's very very difficult. Um, and a lot of people think that they're just zip files and it's just really not. And the other thing too that is I I deal with a lot in the in the batch is let's say you are automating Salesforce, right?

05:16 And you have a bunch of traces and you have screen captures of people using Salesforce. So you have 100 billion hours. You have all the data that you could possibly capture. Then Salesforce changes the UI. Then what? You better get some more data, right? Because it's not going to work. And so you can have all the data, you still need more data. And so this idea that it was going to the terminal value is going to be zero is just so so wrong.

05:43 Brendan Emer just just presented this slide at Sequoia and I really agree with it. It is the bottleneck right now. It is not the architecture. It is not GPUs. It is not watts. Um it's largely why does chat GBT still uh you know I just did this analysis and posted on my Twitter. Um, there's no model gets beats random on predicting next seven-day returns on the S&P.

06:05 Literally, if you just like roll a coin is better than every single AI model that you can use in production right now. Um, and so if we had a bunch of traces from like Goldman Sachs traders that are definitely better than random, I would think that they would do better, but they don't have that. And so, how do you get there? Same thing with accountants, doctors, lawyers.

06:23 you need experts on each one of these uh domains for us to uh match or exceed human uh capabilities on it. And like I said, in the last 10 years, despite most venture capitalists turning a blind eye to this, um it's produced over hundred billion dollars of market cap in the last 10 years. It's probably been one of YC's uh best categories that we've invested in.

06:44 And so the mental model, what is the right mental model to think about this? Um I don't know, but I propose something here. If I were Apple and I manufactured these things and I wanted them to be able to deliver groceries to your door or to um bring a a burrito to your house or bring a car and pick you up or turn it on to a flashlight or give you directions, you need these things called apps.

07:13 And if you want the LLM to be a good doctor, accountant, lawyer, carpenter, um trader, uh or therapist, right? a lot of people using for that as well. um you're going to need data in RL environments and if you don't have upto-date very good curated data then your LM can't do those things and so may and so a lot of people say like how many possible data companies can we have in this space and the answer is how many apps do you have in your phone that's probably the answer I really do think about it like that and then

07:45 even better on this analogy is does it make sense for there to be an Instacart only for Apple and an Instacart only for Android or should probably just be one company or should Apple get into the Instacart business and start delivering groceries? Doesn't make any sense. And so some of these it makes sense like Apple should and Android should have a flashlight functionality because that's kind of easy to do.

08:09 But like for a lot of things it's really really difficult to stand up the entire Instacart network and then start competing with Instacart if you're Apple. Like why? Just that's not what you are great at. And in the same way going really deep into being a great doctor like dealing with HIPPA and all that stuff. Should Anthropic uh uh um OpenAI, uh Google, Apple, all these companies all get really great on curating an AI doctor or should you just like use one company that does a great job of creating a environment, has

08:43 a network of doctors, curates all this prep data, uh you know, parallel uh data for given a specific patient. here's one trajectory, here's another trajectory, and and a doctor is preferring one or the other. Probably just do that. Have one company that just focuses just on that. And that's what we're seeing. All right. I'm very excited by uh the speakers that we have uh tonight.

09:04 Um May couldn't make it. She had got sick unfortunately. We're going to try to squeeze her into the next one. Um but we have uh Vincent Chen, who is a a Hazy alumni, one one of the founding team members of Snorkel. uh grew it to a billion dollar market cap now and and well beyond I think. Vololo, founder of Inception Labs, Cornell professor and expert surfer.

09:32 Um and then Shane uh MIT PhD uh student just defended focused on pre-training uh founded the data provenence initiative and then recently joined anthropic. Please help me give a round of applause to this our speakers. [applause] and Franuis. >> Wonderful. Thank you, Francois, for the awesome introduction and thank you for giving data its flowers. I feel like we've been trying to shout from the roofs about this and uh it's awesome to see it come front and center these days.

10:05 My name is Vincent. I'm one of the founding team members at Snorkel. I uh started our uh Frontier Lab business at the company and now I lead research on our benchmarks and evaluation at uh the company. I'm going to talk about uh scaling expert supervision. Um, and I'll talk about it. I'm cheating a little bit, but I'll talk about a few research themes and how they've evolved over the years.

10:25 We've been working on data for over a decade now at Snorkel, dating back to our roots at the Stanford AI lab. And um our key thesis is that scaling expertise, actually giving leverage to experts in the field, doctors, clinicians, um journalists, people who actually have the spec in their head for what good looks like is the real bottleneck for building really effective data sets.

10:46 And effectively, that's what all of our research is about at the company. So I'll talk to you a little bit about that. As I mentioned, we're a frontier lab focused on data in particular. Um we're uh super excited to be you know partnered with uh effectively every global frontier lab and uh Frontier um you know Fortune 10 enterprises uh on the data problem in particular and each one of these engagements again is anchored on this key bottleneck of scaling expertise.

11:10 How do we actually get the judgment and knowledge out of these people's heads and into the data sets that they're working on? And so I first want to start by framing the problem and how it's evolved over time. Expert supervision, right? The process of taking what is in experts heads, what is in messy documents or knowledge corpuses um and putting it into really effective data is a real bottleneck.

11:34 There's a real process that goes from okay this is raw data to something that can that can be used for evaluation and training and this has evolved over time right data 1.0 know as I'll call it was uh basic labeling in Q uh you know for question answering for example right these might have been thumbs up thumbs down against uh kind of preference labels um basic you know prompt and response pairs and you know let's say it's 30 seconds of human judgment right to produce one of these labels as Frantois alluded to the

11:58 shape of data today is evolving significantly right now we have entire worlds that we're building against um that represent tasks and rubrics and verifiers and really nuance grading mechanisms all packaged in Docker environments um that actually need to represent the types of spaces that these agents are going to operate in. And these could take you know uh single digit to you know triple digits of hours for humans to develop on their own.

12:26 And so the key bottleneck here is really how do we scale expertise so that we can effectively build these types of data sets when experts you know are are one there are only so many of these experts in the world with increasing complexity and they only have so much time in a day. And so let's start with data 1.0. I know right uh this is a problem that I believe still exists today but when we started snorkel um I want to you know share a little bit about how we thought about this problem right the the problem of manual

12:50 labeling right with the imageet example that Francois gave um there are a bunch of problems right uh one it's not a scalable approach um think of the cost of manual labeling as an O of problem for every single data point you need a manual label you need um new cognitive effort to actually develop that two these types of approaches aren't robust to noise right you can Imagine that the only way to actually uh reduce noise in these settings is to um you know uh introduce redundancy.

13:18 So you need a k byn um relabeling effort to actually uh you know reduce noise in these settings with changes in spec you know schema task definition. You need to start from zero and critically there's no provenence. There's no notion of what what is my rationale? How did I actually think about this problem? And so this was the key challenge that we faced you know up to a decade ago and still face to today in many ways where the problem of manual labeling only um compounds in expert domains.

13:48 Think of a you know MD PhD or a cardiologist in a very niche subdomain. How do you actually get them to produce these large large corpuses of MRI data sets or you know EHR uh data? Uh it's actually fundamentally intractable in a lot of these settings. And so that is the key problem to solve in some of these um kind of manual uh uh labeling settings.

14:08 And so the the line of work that we worked on here uh we called kind of data programming. Our CEO Alex was was a kind of grad student at the time and we um all kind of contributed to this work. The key intuition here was we want to encode expert supervision in software and there's a few benefits when you do that right you get the scale of software. You now get to label data programmatically.

14:29 You get the adaptability of software. you can refactor it and adjust it over time as your spec changes and um critically you can actually audit it and have conversations about it and collaborate on it. Um and so the you know in a nutshell right a bunch of our kind of key um grad grad school work in a in a nutshell was was this uh one on the left hand side um the main idea here was um to first model expertise as uh labeling functions right so this could be a number of different forms this is a pretty general uh

14:56 abstraction but the main idea is um if you express the ration or reasons why people are labeling spam versus not spam into specific heruristics this um helps get that knowledge out of people's heads and into a form factor that's actually way more reproducible and scalable. Number two, um, in the middle, the challenge with this is obviously that, uh, these signals, uh, these sources of supervision overlap.

15:18 They're inaccurate. Um, and so we introduce a bunch of theory and work to actually, um, work through this notion of weak supervision, right? How do you actually understand quality in these settings where uh, signals are overlapping and your sources are are weak or aren't, you know, fully ground truth? And at the end of this um taking these uh D noiseis signals and using them in kind of end models that are noise aware help generalize this beyond um you know the coverage of the initial labeling functions.

15:43 So one click down you know the intuition behind some of this and the label model without getting into too much of the of the gory details. Um number one the goal here is to model um each voters's accuracy in a fully unsupervised way. So the analogy I like to share is hey you have a number of students in your class with different levels of skill or quality.

16:04 Um you don't have a grading key, you don't have an answer key. How do you estimate the true ground truth answer when you only have the votes from each of these students? And so that's the fundamental kind of modeling problem you're trying to introduce here. Um you want to learn this noise model and understand each source's um quality effectively. you know, given that you don't have any ground truth in the first place.

16:28 So, uh, step one again is to kind of learn the voters's accuracy. Step two, this is this is Baze, right? You're trying to kind of compute the the probability um of of the ground truth solution given each one of those voters um uh uh kind of actual votes. Um, and then three, if you train a kind of noiseaware model, um, you're able to actually extend the coverage of this label model and minimize some of the noise in in uh, broader distributions and and scale this a lot more effectively.

16:55 So, I'll zoom out for a sec. Right? The main intuition here was a lot of our work early days was about scaling expertise via introducing labels and expert judgment as software. And one of the key bottlenecks there was actually denoising the sources of signal that these came from in in in a a regime where you were missing ground truth and um you know some of these techniques uh we still use today in a lot of our kind of production settings.

17:21 So I want to talk briefly about data 2.0. Now you know as the surface area for data and frontier progress has expanded um it's grown in uh complexity and importance as well. And so let's let's use coding as an example here. you know, I have plotted on the x-axis uh complexity, right? Input complexity, how complex are your prompts and the specs that you're giving models, output complexity, environment complexity, are you working in just Q&A settings now, or are they fundamentally new, you know, uh environments where you

17:48 give it YOLO access to your desktop? And on the Y-axis, we have sequence length. How long are these agents actually working in practice? Now, you might think for a domain like software or coding that uh the eval are actually saturated, the data is actually saturated. And I would push to uh contend that as the frontier advances, the data challenges actually continue to grow, right?

18:07 We're we've seen basic eval like human eval saturate at this point, which is which is true, but we're still seeing, you know, um a big spectrum of uh you know, terminal based agents continue to grow. Uh program bench, you know, I think the latest model just cracked 1%. Um we introduced the benchmark called senior SWE, which I'll talk about in a second.

18:27 But as the complexity and responsibility of agents, you know, grows, the importance of data that you're uh producing to both train and evaluate these models also grows. With this in mind, I want to anchor on some recent work that we've done uh from a little bit uh later than the last decade um which was a senior SWEBench. And so the the key here, we actually uh were very humbled and privileged to work with the original SWEBench team out of out of Princeton on this.

18:51 Um the key idea here was we're already using coding agents like software uh like senior engineers. We're vibe coding. We're trusting them to make architectural decisions to refactor entire swaths of of code, but we don't have good ways to evaluate them. We're still evaluating them as as junior engineers. And so the key challenge we wanted to solve here was that we wanted to build a benchmark.

19:11 We wanted to build data sets that were really representative of actual work that senior engineers would produce. We wanted to scale the expertise needed to produce and build these types of data sets and uh build a really highquality benchmark that uh represented all of these factors. And so I'll talk you through some of the methodology we used to get here.

19:29 Obviously we won't get through everything but um you know hopefully build some intuition for how some of the methods we've used have have evolved over time. And so a little bit about the task themselves, right? So uh in senior Sweetbench um the task design specifically required many points of expert supervision or expert touch points. So on the left hand side uh this is a harbor task.

19:49 We're big fans of harbor as an eval um uh framework. Um these are instructions that are natural language instructions. So the the key diff here was instead of representing you know if you're familiar with a Swedebench or or kind of traditional coding benchmarks if you actually look at the data if you actually look at the tasks a lot of the samples are very oversp specified very kind of EDDD level um you know guidance for what to do what not to do we wanted to represent more realistic higher level abstractions in terms

20:17 of how we actually interact with these agents in practice so more of a Slack message here's a here's a dump of logs you know figure out what to do with it or um here's a few users stories about an idea that I have. Um can you help me implement this? So actually injecting expertise and realism into the instructions was a super non-trivial part of building this.

20:34 Um on the right hand side um you see a whole reward phase which we uh spent a lot of time designing and specifically um calibrating as well. I'll go into a little bit more detail but the intuition here is we wanted to capture a number of different components of how you actually measure these agents in practice. So not just um is this correct or mergeable but does this exhibit taste?

20:54 Does this exhibit what you'd trust a staff or senior or principal level engineer to actually do in your codebase uh completely unsupervised? Let's go a click deeper into the specific uh reward design. Um and this was a bit nuance and again an area where we wanted to get creative in scaling expertise. So we had you know snorkel engineers and researchers.

21:14 We have a really strong network of very senior principal staff level engineers um but not unlimited time. And so we wanted to find ways to scale their intuition and efforts rather than having them handgrade every single one of these samples and agent trajectories that came out of this. So the axis we tried to articulate here um there there's a trade-off between reliability and flexib uh flexibility when it comes to traditional verifiers and rewards especially in the software domain.

21:40 On the top you have um high reliability and low flexibility. These are pre-written verifiers and think of these as unit tests, right? These are tests that reliably execute against your codebase. They're um actually um running against the code so you know that they're doing the thing. Um but the challenge is they don't actually adapt to any solution, right?

21:57 If you have um a you know post/profile implementation versus a um you know another way to implement a way to kind of update a user's information, you might actually have a false negative in the verifier, right? might actually penalize behavior that is fully okay and fully valid um if you're too constrained in your verification approach. And so on the other side of the spectrum, right, low reliability, high flexibility, you have LLM judges, right?

22:24 This is a very common and effective way in many cases to actually adapt to different solution shapes, right? The um code can be a little bit more flexible. uh you're actually just asking an agent or LLM to look at the code and specifically um you know grade it uh using its own kind of uh calibrated or unccalibrated intuition. Um and obviously the challenge here is that this can be really unreliable because you're um not really exercising any of the solutions.

22:49 You're not exercising the code path directly. You might be just, you know, asking the agent to kind of take a glance at the code and it's it's hard to actually uh control for false positives here, right? Where you may o overreward plausible but incorrect solutions. And so we found a middle ground for this which I'll go into a little bit more detail and introduced this notion of a validation agent uh which specifically tried to capture and scale the expertise of a bunch of our senior researchers and engineers and

23:15 experts in our community and and network um to one express the user stories or kind of specification of what they thought good looked like and two use that specification to then write deterministic tests against the code surface that was actually relevant to you know the solution space. So um a simple idea but did take a lot of calibration and effort to actually um come up with this notion of hey how do we actually capture the expertise of of someone who's you know defining user stories for a particular task while

23:47 actually exercising the real code path. So again in a little bit more detail right what does this actually look like in practice the input to this validation agent think hey I have codeex I have uh clawed code it generates a patch against my instruction set the expert produces what we call the validation spec so this was just a few bullet points think a slack message of okay here are my user stories here are a few you know uh functional or non-functional requirements not so much that it was oversp specified and overly

24:13 prescriptive about a specific solution but uh high level enough so that it to capture the space of you know what we wanted the model to do or not do. We then had a validation agent take the patch and the validation spec and specifically in uh implement test scripts. So these were uh deterministic um scripts that would uh execute and and run over the code itself.

24:35 And at the end of this, we would uh score against the both both the execution and use a judge um to ensure that the runs were were kind of sane or you know uh resulted in kind of collusion or reward hacking or some sort of behavior that we thought was um not valid for the trial. And so this this idea of encoding expertise in a way that um was still scalable was really the crux of how we tried to design this validation agent to map to dynamic implementations right in the specific codebase.

25:05 Um and so we did a lot of work actually to calibrate this. We aligned these against you know specific test engineers internally and in our network. Um we introduced LLM judges that measured things like uh fidelity, completeness, collusion and ultimately each test was parameterized so that um you know in the validation spec you you can think of it as like a ramble of kind of um hey what is the shape of the type of use cases edge cases I want to capture without having to write you know the full spec at the end or the the

25:31 full tests you know at the end of the day which could take days to weeks to months. So this is um live now and one thing I want to uh point out before you know talking about the results which are kind of fun. Um we introduced this notion of a tasteful pass. Um this is a new metric that we introduced in this benchmark to specifically measure not just correctness or mergeability but a more nuanced definition of is this actually code that aligns to your codebased practices.

25:57 Does this actually map to um you know how a senior engineer would act in practice? Does it minimize bloat in terms of patch size? Um we merged that with uh notions of correctness to actually um rank a bunch of these models and remarkably um and we double and triple check this uh Fable, Opus and Soul are all tied for first place as of uh last week. This is pretty exciting because it means that um you know the Paro Frontier is definitely getting pushed in these cases, but this is a kind of live dashboard and a living

26:27 benchmark that we've been keeping up to date. So definitely reach out and check it out if you have um if you're curious about it. This is some of our recent work um on this topic. And so I want to definitely give some flowers to the team here. Henry, our co-founder, uh was the was the lead here. We were very humbled to work with Cararthik's group at Princeton who led the original SweetBench and uh our chief scientist Fred uh who has the lab over at uh uh Wisconsin Madison.

26:49 Um and some of his students were also involved. And so I'll zoom out and and wrap up here. Um as we enter data point 2.0, this is maybe the the takeaway here. As we enter data 2.0 know and see a lot more complexity. We need a lot more data research, right? It's not just a problem of throwing humans at these tasks. These days, we need a lot of thoughtful design to give these experts, software engineers, doctors, uh lawyers, people who actually understand the spec leverage to exercise their own supervision and judgment

27:16 in these data sets. And um you know, this this slide at least shows a view of all the axes that complexity is going to continue to grow in, right? The environments are going to get more complex and dynamic. the outputs are going to get more and more unverifiable and nuanced and subjective and the autonomy of these agents are going to also continue to extend and you could imagine every one of these axes introduces compounding complexity and so it's really a research question.

27:41 It's really a research problem to think through how do we scale and um provide experts more judgment and that's really what we're focused on and encourage the community to to work on as well. And so here's a very concrete ask. Uh we need more benchmarks and we think this is actually a really high lever way for folks to drive new data research. We're super humbled to to work with a number of the folks on the screen from agents/exam um over at Berkeley continual learning bench oorld uh the terminal bench folks.

28:06 Um we've learned a lot working with these folks and um in general we're we're uh very excited to see a lot more benchmarks and so we like to put our money where our mouth is. We have this notion of a open benchmarks grants. Um hopefully this is us actually a research a resource to folks in the community. We're very excited to you know accelerate and and focus on more research that is out there and help you accelerate your data devel data development and partner as a as a research team.

28:32 But um yeah, we're really excited about the future of benchmarks and data for data 2.0 and thanks so much. [applause] >> All right, next up we have Volo. >> Uh okay, great. Thank you for having me. Super excited to be here today to tell you about some of our uh work some of the work that we've been doing at Inception on training uh real world large scale diffusion language models uh with uh my co-founders Stephano and Aditia and a really really talented team of engineers and researchers.

29:01 So in short uh what we're working on is a new generation of language models that is powered by diffusion. And what that means is that instead of generating tokens one at a time sequentially left to right, a diffusion model starts by generating tokens all at once uh starting from an initial guess of the sequence. So starting from some some kind of noisy initial version of the output and then producing all the tokens in parallel over multiple steps of refinement.

29:31 We're very excited about this technology. we think is going to be the future of language models. And in particular, a very important advantage these models have today is speed. Because these models can produce multiple tokens per step, they can produce many more tokens per second and they can reach speeds at over a thousand tokens per second uh which is way beyond what is achievable with uh traditional ultra reagressive modeling.

29:56 There's all kinds of applications for ultraast inference in real time AI. One area that we've been working in uh a lot is real-time voice. Um so voice agents for example uh in customer support uh but also in other domains like education. Uh so these are agents that uh synthesize voice and talk to you in real time. Usually uh the voice uh state-of-the-art voice pipelines are still built on a cascaded architecture where you have a uh speech to text system, a texttospech system at the output and at the middle you have an

30:33 LLM. The overall latency of the system is highly bottlenecked by the LLM. This is a critical critical piece of this workflow. And if you can make LMS go much faster, if they can go at 1,000 tokens per second like our Mercury 2 models are able to achieve, then you can make real-time voice interactions feel more seamless or you can deploy a bigger model or you can get the model to reason for longer which will then significantly improve your quality.

30:59 So this is a slide that shows the performance of Mercury 2 on voice benchmarks compared to other models. And what you see is Mercury 2 draws a a new parto frontier of quality and uh and latency. So latency on the x-axis, quality on the y-axis. Uh so we have a a new parameter frontier that's achievable with a fusion. I also want to highlight some other models here that are baselines.

31:27 So here for example we have a uh 120 billion parameter GPOSS model running on cerebras and a diffusion mercury model can achieve both higher quality at least as measured here by tobench and I'm going to argue on real data as well uh and it can also run faster. So this is really exciting because uh so again three are specialized chips uh designed and built to make other aggressive models run really fast.

31:52 If you have diffusion, you can achieve similar speeds on GPUs by having more intelligent software. So you can build software to make models really fast instead of hardware. That's really exciting. You can deploy these models on uh on on a lot more GPUs that are more easily available. Um but to build a really good voice models, algorithms and diffusion is one component, but the other part that's really really really important is the data.

32:17 uh you need data both for training the model and for eval right now perhaps the most widely used and representative benchmark for running evals is tbench uh tabbench has a few problems first of all tbench doesn't really capture all the range of complexity that you see in real world data uh so if you look at a tabbench environment it is it probably has an order of magnitude fewer specifications than you would have in a in a real world uh setting where like a business would be doing real world customer support.

32:48 There's fewer tools in Towerbench. Uh it doesn't have certain kinds of specifications that you would want to provide. Uh and then another problem with Towbench is that it's extremely benchmaxed. If you go to your favorite benchmarking website, you're probably going to see most of the models achieving uh scores that are in the '90s. But then if you run these same models on real world production logs, uh you're going to get much lower scores, and there's also going to be much more variance across models of different

33:15 sizes. So data is a key key ingredient of building the kinds of performant models uh that that we want to build uh in addition to the algorithms. Now our approach for getting good data for our models involves a system that we call Dowo Forge which uh synthesizes a wide range of realistic RL environments similar to Dowbench based on real data based on real user interactions or uh either based on data that we're getting from our data providers or we also have partnerships with companies that are using uh this model in

33:48 production and so we get a lot of real world data that then allows us to synthesize uh talbench like environments across different domains which can then be used for evals as well as for training the model. So this slide here summarizes or gives an overview of tao forge. Uh taforge is an agentic system. So it's a harness that orchestrates uh a large number of different agents and it produces this output synthesized so synthetic RL environments that are similar to Towbench.

34:20 The input to Dow Forge is a description of the kind of environment that you would like to generate. So here for example, you could ask it to generate a banking environment as well as artifacts that represent real world usage of users in that real world usage of the model in uh that target domain. The first step is to synthesize uh an initial environment that is based on that data.

34:46 that involves for example a policy that specifies the kinds of uh uh task or the kind of domain where you want the model to operate. So for example, if this is meant to simulate customer support in banking, then you could generate a policy that describes how the bank would operate, what are the hours, who are the users, different accounts, maybe synthesize a small database.

35:07 Uh and also uh it creates tools that the model can use to then interact with this environment. Uh again crucially this can be uh conditioned on real usage of the model which ensures that this environment is representative of how the model is going to be used later in in production. If this data is not available, we've also created what we call the business knowledge graph which is data that has been crawled all across the internet and that describes various representative businesses.

35:33 uh so we can also synthesize uh uh domains for which we don't have real world data but we have crawled the internet to gain real world knowledge about these businesses. Now given an environment then the most important next thing that we want to generate are tasks which means these are tasks that uh uh so so we're going to have uh simulated users that will try to achieve certain goals in this environment and the agent will assist them in these goals and we need to synthesize what those goals are.

36:02 In order to do this we start with what is called a database of seeds. Uh so these are abstract scenarios. For example I want to open an account, close an account, I want to change my phone number. uh I would like to I don't know get some information uh as well as personas which are um certain types of humans that might be interacting with the model given that we have an environment we can take our library of scenarios and other seeds and specialize it to this domain again by invoking an agent uh and then once we have a

36:32 good database [clears throat] we can start to generate tasks. So again these are real world interactions that a user would have with these models and then we will simulate those users using other agents. Now getting a good set of tasks is also non-trivial. Uh we need to strike a careful balance of tasks that are uh not too easy to solve. So if a if a model consistently solves this task, it's not useful for learning.

36:57 And conversely, if the task is too hard, there's also not enough learning signal. So there is an iterative procedure where we filter and reconstruct tasks based on the ability of the model to solve them. Uh and to do this we use these go these what we call uh hardening traps which means that uh we can uh modify the task to make it more difficult. So for example you can take away certain information or you can make the ask more complex.

37:20 Uh so you can do all kinds of uh tricks to harden the task or you can also filter out difficult tasks uh until we get something that we feel strikes a good balance between being realistic and providing learning signal to the model. So again the output here are RL tasks and then uh of course this is continuously inspected by looking at real world data.

37:42 So uh models are well first of all these environments can still be verified the harness can be updated uh and also models that are coming out of this environment we get real world feedback from users and we can use that to further refine the harness and further refine this uh synthetic generation procedure. So as an example of what this model can achieve uh here this is an experiment where we used our latest preview model mercury 2.5 um uh so before it was uh trained on any sort of domain specific data you know it

38:15 achieved about 50% accuracy and training it on an initial set of tasks synthesized from tforge improved performance on another set of environments by over 23% matching the performance of uh all kinds of state-of-the-art openour or is in closed sourced uh model and here just to clarify the setup is that uh there are there's a diverse set of environments and businesses so for example I don't know banking or you know airplane um booking airplane tickets and uh you know getting doctor's appointment so you can have a whole

38:49 range of businesses and you can split that into a test set and a training set you hill climb on one set of businesses and you test on a different set of businesses uh which ensures that uh which which helps reduce overfitting. Um and and again these these these these tasks are still especially the test set is closely derived from real world logs which gives us confidence that this will correlate with real world performance once we deploy into into production.

39:13 Um, so this is just a a bit of uh a bit of information on the kinds of techniques that we can use to make our model really high quality, not just fast, but also improve their uh intelligence in some very specific priority domains like uh voice. Uh and if you'd like to try these models, they're available. Uh so they run at 1,000 tokens per second. This is the pricing.

39:36 And even though I mainly talked about voice in this talk, uh we also have uh customers across other domains including search as well as code. Uh and so these are all domains where uh mercury 2 models are really good for latency sensitive tasks. Uh and there's if you're interested in feedback, we have companies and other companies that are using these.

39:58 Uh so happy to tell you more after the after the talk. And maybe I'll just briefly add by saying that we have a program for startups. If you are in YC, we have a we have $500,000 in credits that we're very happy to give away. Uh if you're interested, please uh grab me and uh I would love to tell you more. Thank you. [applause] All right, next up we have Shane.

40:25 Awesome. Thank you. Thank you so much for your attention. I think I'm the last talk and uh I'm Shane. I just graduated from my PhD at MIT and I think this is my favorite project uh during my 5-year PhD. It was work that I did while interning at Google. Thank you for the TPUs to make this happen. Um we basically looked at multilingual pre-training and within that transfer between the languages.

40:51 So the synergies, interference and interactions between the different training sets uh data set sources that are different languages. While I walk you through this project for the next 10 minutes, you can imagine all of these experiments and all of these results and methods could be generalized to many different sources within your data. They don't have to be languages.

41:11 They could be um different domains or different quality sources of data, different things um however you want to splice it up. And I think that's important because increasingly when we think about uh our model's capabilities, its risks, its limitations, we think about how all of those different pieces interacted and came together. So diving into this, I'm going to talk a little bit about why this is important, motivating it a little bit beyond English.

41:38 Then I'm going to go through really quickly, rapidfire, some of the research questions we asked and the answers we arrived at before bringing it together. So this was presented at iClar earlier this year with these phenomenal folks at Google, Udub, Stanford and some other places. If you look at scaling law and even mixing law papers in literature right now, uh they are 99% about English training data and English evaluation.

42:04 There's very little about sort of the rest of the world and the community. Uh which is actually kind of shocking. And so this is thinking what if the objective was a single language that wasn't English or multiple languages a cluster of them and exploring that domain. And why is that different than in English? The reason is because there's severe constraints when you go past the first few languages that are very abundant online.

42:28 And we also uh provide toolings and methods both for scaling laws, mixing laws, fine-tuning versus pre-training and other decisions that developers have to make. And this has implications for uh developing models for your own culture, society, language and also trying to figure out if you are Turkish um what are the constraints in pre-training for uh Turkish language models, how much will they lag behind uh language models for English based off of just the availability of data that's there and what synergies and

42:59 interference we can expect in pre-training. So let me start with the problem setup. Very simply, let's pick a language. We're going to pick Thai because there's something like 80 million speakers in the world. It's a very unique language, but we could be talking about Swahili, Polish, it doesn't matter. The point is that in Madlad 400, a popular common crawl based pre-training corpora, there are 0.6% the number of tokens in Thai as compared to English.

43:28 So less than a percent of the amount of English data that you have. You know, some frontier model, CHBT, whatever it is, we don't know. but it has some training mixture among the natural languages and it's probably going to roughly follow like every other language mall the distribution you know they'll do different sampling techniques and things like that but you're going to roughly have more English than anything else followed by the next languages you care about that are more abundant more uh heterogen heterogeneous

43:55 um all the way down that list and by the time you get to Thai it's a tiny sliver of the overall mixture much less than 6% and so the performance performance on Thai is going to be pretty poor. Um, it might be pretty pretty good overall because it's a massive model, but it's not going to be great for Thai speakers. And this is shown uh in the literature and in evaluations.

44:20 So, you might say, okay, let's train a model just for Thai. We're going to monolingually only train on all of our TAI data. But the problem is there's so little of it that we end up repeating it again and again and again. And those are those dash lines, epochs. And you've overfit to your tie data. You need a much smaller model. And so actually, you don't do very well there either.

44:42 Ideally, what you want to do if we skip ahead to the solution is something like this. It's actually a mix where you use a lot of your tie data, but by the time you're hitting severe diminishing returns, you're also incorporating, this isn't a curriculum. This is all, you know, mixed together. You're using highquality synergistic data that happens to be English, Indonesian, Malay, Lao, uh, Croatian, it turns out.

45:06 But you're not going to know that because this isn't just about what language families are similar. It's about what data empirically is not noisy and that other source is actually helpful, covers similar topics. Um, and that is very distributed and uncertain on the web. It doesn't just mean that they are from the same language family. So it's something you have to empirically measure.

45:28 You can't just bring a linguist and they can theorize about linguistics for this particular case. So how do we get to the fantastic Thai model or sahili model or Turkish model and figure out the right mix and the right model size? First we want to measure language synergies and this is where a lot of the contributions of the paper comes in. There's many ways you can think about doing this.

45:51 And the way that we landed on was imagine this. You have a training curve. So over your training steps, the red line is where you're training only on Thai data. So it's monolingual. So it does pretty well, but it flattens very early. Now imagine that compared to uh models that are trained 5050 on Thai and English, Thai and um Telugu, Thai and other languages.

46:16 And you can see that those learning curves are much higher, meaning that they're not as good. And so actually the distance between these curves tells you something about how good that language is in being helpful for Thai. And so we can say, okay, well, Indonesian is better than English, which is better than Telugu because that line is longer, the distance.

46:37 Um, and this efficiency gap can be formalized into something that looks like this. And let me abstract all this away. Uh you don't have to go into too much detail. If these two lines are really close, the number is big and positive. If the lines are very far away, it's going to be a negative transfer, meaning there's interference. These languages are competing for tokens or neurons in order to represent one another and perform well on them.

47:06 And if you do this over and over again with many tricks that I'm not going to get into, you get this big cross-lingual transfer matrix where red means high synergy and blue means high interference. And so if you look at, you can't see it, but imagine you could zoom in and look at Spanish, the row. The bright red uh spots empirically happen to be Portuguese, Italian, um, and French.

47:31 And the most negative harmful language um is Japanese. Meaning if you train with Japanese, it's going to hurt your Spanish. And so this is all empirically sort of born and there's, you know, some surprises in here, some interesting things. Some languages are more helpful broadly than others. Um and it's complicated. The other really cool thing about this matrix is it's at one fixed size of language model.

47:56 If we increase the size of the language model and make it much bigger, then actually a lot of these blues start to turn red or deeper red, there's more synergy because the model's bigger and can accommodate uh understanding multiple languages at once or together and seeing their common patterns. But if the model gets really small, all of these turn to blue and they all interfere competing for space within the model.

48:19 All right, quick question for the audience. who thinks that if um Portuguese is helpful for Spanish, that means that Spanish is helpful for Portuguese and that symmetry exists uh from what we measured. Raise your hand if you think that is true. We have a few people. If you think it's not true, raise your hand. Okay, it's kind of 50-50. Well, actually, it's kind of hidden on the screen.

48:47 I know it's late. Uh it's not symmetric as you can see. Um and actually there's this weird sort of like uh branching factor that happens and this is important because if you're a practitioner and you do experiments you say okay Telugu is really helpful for Swahili you can't assume the opposite you have to go measure it and so that's where this breaks down and we actually show that okay second question you can redeem yourselves um what is more helpful do you think if two languages share the same script or if they share

49:19 the same language, family. Who wants to vote for family? We have some. Who wants to vote for script? All right, congratulations team script. They both matter, but script matters a little bit more probably because of tokenization artifacts and how those are represented. If you're taking pictures, don't worry. It's all online. I will point you to it. Um, I'm going to go through in the last three minutes really quickly a little bit of math.

49:46 We have this great matrix. So we have all these numbers and relationships between languages. But the last step is how do we actually create a scaling law from this? How do we actually understand how to predict estimate loss or figure out the best mixture of languages for a given target which is our original goal. You have to fit scaling laws. Those of you that are familiar with Chinchilla probably remember this.

50:07 You predict the loss based off of the model size and the amount of data you've trained on and you fit it using these blue parameters here. you fit those. Um, however, if you have a multilingual data source and you're trying to figure out how good it is on French, the thing that matters most is how much French data you had and if you have tons of other data, you know, how is that factored in?

50:30 1D is not helpful. You need to model all of it. And so, um, that's what we do. There's many ways to model this. We explored many options but simple solution that actually works really well is to break down chinchilla's d into a composite of monolingual transfer languages monolingual source in this case Thai the close transfer languages in the matrix plus a bucket for everything else that looks and yeah we account for diminishing returns when you run do multiple epochs of certain data there's a lot of details long story

51:02 short it looks something like this and uh the tow how is sort of a waiting factor that you can learn from the matrix. I'm going to rush along in the interest of time. But you get bold numbers in a table state-of-the-art. Yay. It works. It works really well actually. Maybe because a lot of people can't run 700 pre-training experiments. Maybe because this is unders underserved and people aren't looking at this enough.

51:24 But either way, I think this is really useful machinery to use for mo for uh mixing multiple sources and understanding how they interact to predict the final loss for your model and how to scale your model given what you have. So it gets us back to this. I'm going to wrap up by saying we did some experiments to say you have a big pre-training models available that are multi language.

51:47 You just fine-tune or maybe you should pre-train from scratch for the language that you care about. We tell you which to do based on how much compute you have. We also look at the curse of multilinguality. So if you um want to increase the size of a language model from four languages and you want to retrain it for eight languages, how much more data do you need and how much bigger does the model need to be in order to maintain the same performance as before?

52:15 We do a bunch of math. It's very cool and we show you exactly what to do as a practitioner and it actually holds really well over different target languages. So I'd recommend consulting this if you're interested. Thank you so much. Appreciate your attention. [applause]