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For the first generation of large language models, competitive advantage was straightforward: get more compute, crawl more of the internet, train longer. Pre-training data was the fuel, and the internet was an effectively unlimited source. Every lab had access to roughly the same corpus. The differentiator was scale. That dynamic has fundamentally changed. The models that are pulling ahead today are not the ones with the most pre-training data. They are the ones with the best post-training data — and post-training data is human data.
The best evidence for this shift comes from OpenAI. For eighteen months, every flagship model — o1, o3, and the GPT-5 series — was built on the same base model: GPT-4o. The performance gains that made these models successively better did not come from more pre-training. They came from scaling up post-training: more RL compute, more human feedback, more expert-crafted tasks and environments.
This is a profound realization. The primary driver of model capability has shifted from data you can scrape to data you must create. And creating high-quality post-training data is orders of magnitude harder than crawling the web.
Pre-training had the entire internet as its training set. The equivalent corpus for RL and post-training does not exist yet. Most tasks and data for post-training must be constructed from scratch, often by domain experts who understand both the task requirements and how the model will be evaluated. This labor intensity is precisely what makes it a competitive moat.
The preference signals, task designs, and evaluation rubrics that a lab creates are proprietary. They reflect the lab’s specific strategy for what their model should excel at. If OpenAI optimizes for PowerPoint and Excel tasks while Anthropic focuses on code and biology, their post-training data will be fundamentally different. This specialization means that human data will become increasingly scarce and valuable as labs guard their data more closely.
A preference judgment from a board-certified radiologist is not interchangeable with one from a general crowdworker. The expertise is embedded in the data itself. This is why domain knowledge matters more than speed in annotation — the training signal carries the annotator’s expertise, and no amount of volume compensates for missing expertise.
Annotation guidelines, quality control systems, inter-annotator calibration, bias auditing, and workflow management all need to work together seamlessly. Building this infrastructure is expensive, and scaling it without losing quality is one of the hardest operational challenges in AI today. The organizations that have built this infrastructure have a structural advantage that is difficult to replicate quickly.
Anthropic has taken a deliberate approach to building a broad human data ecosystem. The company works with more than a dozen RL environment companies as contractors, often becoming the first customer for newer vendors and providing tips on environment construction. This strategy commoditizes certain types of environments through vendor competition while maintaining access to diverse data sources.
OpenAI has invested in the opposite direction: building an in-house human data team to reduce reliance on external providers. At OpenAI’s scale of data consumption, the margins paid to vendors are significant enough to justify internal investment. The company has also built an internal platform called Feather for processing contractor data and aggregates data across its various programs — ChatGPT Agent, coding, consumer products — feeding it back into mid-training to create a compounding advantage.
Google DeepMind is uniquely positioned because it owns the underlying platforms. Sheets, Slides, Docs, Gmail, Maps, and dozens of other products generate real user behavior data. The company’s product managers have deep visibility into how hundreds of millions of users interact with these products, providing direct signal for what strong model performance should look like. The challenge for Google is organizational rather than technical: leveraging this user behavior for model training requires coordination across teams that have historically operated independently.
Chinese AI labs are earlier in scaling RL-based post-training. Qwen is estimated to spend around 5% of pre-training compute on post-training. Chinese VC firms are actively trying to build local data foundry competitors to serve the ecosystem at lower costs than western providers. Successful homegrown data businesses will accelerate the transition to RL-heavy training for Chinese labs.
The implications extend well beyond frontier labs. Any organization building or fine-tuning AI models faces the same question: where does your training data come from, and is it good enough to differentiate your models? Models trained exclusively on synthetic data or generic public datasets will converge toward the same mediocre performance as everyone else’s models. Differentiation comes from human data that reflects specific domain expertise, use case requirements, and quality standards.
This does not mean every company needs to build a data operation the size of OpenAI’s. It means the investment in human data — the experts who produce it, the processes that ensure its quality, and the infrastructure that scales it — should be treated as a strategic priority. Managed human data providers like Careerflow exist specifically for this purpose: providing the expert workforce and operational infrastructure that most enterprises cannot justify building internally, while delivering the kind of domain-specific, quality-controlled data that creates genuine model differentiation.
The era in which AI capability was primarily a function of pre-training scale is ending. The next phase of competition will be defined by the quality, specificity, and depth of post-training data. This data is produced by humans. It requires expertise, infrastructure, and deliberate strategy. And it cannot be replicated simply by spending more on compute.
Human data is not a cost center. It is the competitive advantage. The teams that recognize this and invest accordingly — in expert talent, in quality infrastructure, in data operations as a core function — will build meaningfully better AI. The ones that continue to treat annotation as a commodity will find themselves perpetually behind.
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