I’ve been reading a lot of AI research lately. Something has been nagging at me: the modern AI research ecosystem has quietly abandoned peer review, and the field has largely stopped noticing. I’m wrestling with understanding what this means, why it bothers me, and maybe recognizing I need to adjust my expectations in these times of incredible, rapid AI-assisted research on AI and AI-related topics.
A Brief History of arXiv
arXiv (pronounced “archive”) launched in 1991 as a preprint server for physicists who wanted to share results quickly before the long formal publication process concluded. The idea was simple and good: don’t lock up knowledge for 18 months behind a slow editorial queue. Let researchers read and build on each other’s work in near real-time.
It worked beautifully for physics. It has since become the dominant dissemination channel for computer science, mathematics, and AI. And in principle, that’s still a good thing. We now have a venue for research that is open, fast, and accessible to everyone regardless of institutional subscription status.
Is this OK? Or has something gone sideways?
The Citation Chain Problem
Here’s the pattern I keep running into: I open a recent AI preprint (something on large language model reasoning, reinforcement learning, or model training) and I look at its reference list. Nearly every citation reads something like:
arXiv preprint arXiv:2501.XXXXX
Not “published in NeurIPS 2025.” Not “Journal of Machine Learning Research, Vol. 22.” Just: preprint.
Some of the most widely cited papers in AI right now are unreviewed technical reports. The Qwen2.5 technical report (Qwen Team, 2024), describing one of the most widely used open-weights model families, is an arXiv preprint with (checking Google Scholar) has over 11,000 citations at the time of this post! The Qwen3 technical report (Yang et al., 2025)? Also a preprint. A paper I’ve recently been studying with my students, TTRL -a paper on test-time reinforcement learning that entire lines of follow-up work have been building on (Zuo et al., 2025) – initially circulated as a preprint before being accepted to NeurIPS 2025, meaning it spent months in heavy citation before clearing any formal bar. The NeurIPS reference has a little over 200 citations already. With respect to the utility of arXiv, as a Mandalorian would put it, “This is the way.”
And then there’s the category that doesn’t even seek conference review: industry technical reports from Meta, Google, Alibaba, and DeepSeek, describing frontier model families. The Llama 3 technical report from Meta (Grattafiori et al., 2024) is an arXiv preprint. DeepSeek-R1 (Guo et al., 2025) – the paper on incentivizing reasoning in large language models via reinforcement learning – circulated as a preprint for months before eventually being published in Nature in September 2025. That eventual publication is worth noting: the community built heavily on it, launched dozens of follow-up preprints, and treated it as established science well before any independent reviewer had looked at it. The formal peer review was really a lagging footnote to a citation trail that was already quite deep and impressive.
What does this means in practice for the AI researcher today? A new paper cites 30 sources, many of which were unreviewed at the time of citation. That new paper is itself a preprint. And within weeks, other preprints will cite it. The epistemic dependency chain is unvalidated all the way down. Should this be of concern?
Where Peer Review Has Gone
Traditional peer review assumed a sequential process: experiment → submission → expert review → revise → publish → cite. That model has effectively collapsed in AI/ML for a few compounding reasons:
- Speed asymmetry. Peer review takes 6–18 months. The field moves in weeks. By the time a paper clears formal review, it may already have dozens of preprint descendants.
- Venue congestion. Top conferences like NeurIPS, ICML, and ICLR, to name a few, accept roughly 20–25% of submissions at best. This means a large fraction of legitimate, solid work never clears the bar, not because it’s wrong, but because the venues are already overwhelmed.
- Industry reports bypassing the queue entirely. Many of the most-cited papers in AI right now aren’t rejected conference submissions languishing on arXiv — they’re technical reports from industrial labs that were never intended for peer-reviewed venues. They describe systems their authors built and deployed, not experiments submitted for external scrutiny. This is a different kind of problem from slow review: it’s the deliberate absence of any review at all.
- Thin conference review. Even papers that do get accepted at major venues typically receive 2–3 reviews, often written in 2–3 weeks by reviewers who may themselves be preprint-only researchers working in adjacent subfields. Having been a reviewer, it is a time-consuming process. The rewards are intrinsic, of course. It forces me to keep up to date, but in a field like AI today that is inundated with research, the process is too slow. arXiv is not the adversarial, months-long scrutiny that characterizes review in medicine or biology.
The result: the word “preprint” has functionally lost its meaning as a cautionary label. In AI, is a preprint now considered a de facto publication? It surely seems to be the case. It gets cited like one, benchmarked against like one, and built upon like one, often before anyone outside the authors’ own institution has carefully checked the work.
Citation Laundering
There’s a deeper problem I’d call citation laundering: a claim gets repeated across enough preprints that it acquires the social authority of an established fact without ever acquiring the epistemic warrant.
Consider how this plays out in practice. Paper A (a preprint) reports substantial accuracy gains on a reasoning benchmark using a new training method. Papers B, C, D, and E (all preprints) each cite Paper A as a foundational result and build refinements on top of it. Paper F then cites B through E, and its introduction reads as though A’s result is settled science. At no point in this chain has anyone outside the original research group independently verified the foundational claim. If Paper A overstates its result (through cherry-picked benchmarks, a subtle flaw in experimental design, or a training setup that doesn’t generalize at all), then all of B through F inherit that flaw.
This is not a hypothetical. There is a growing body of work raising exactly these concerns. Papers like “No Free Lunch: Rethinking Internal Feedback for LLM Reasoning” (Zhang et al., 2025) and “How Far Can Unsupervised RLVR Scale LLM Training?” (He et al., 2026) examine specific training paradigms — methods that use internal model signals instead of external reward supervision — and show that the gains they report tend to follow a rise-then-fall pattern: performance improves early in training, then collapses below the pre-training baseline. Aggregate benchmark numbers, looked at before that collapse sets in, would appear to be a genuine advance. Notably, both of those critical papers are also arXiv preprints.
The specific findings in those papers are about a particular class of methods, not a sweeping indictment of all AI benchmarking. But they illustrate the general risk well: a training approach can produce results that look compelling at the wrong moment in its training curve, get cited heavily in that window, and the problematic training dynamics surface only later when someone looks harder.
Perhaps this is the new form of peer review in rapidly evolving fields such as AI: release a preprint on arXiv, let it get some press, make the rounds on the socials where people (including the authors themselves) can post and hype up their work, or much more preferably, start discussed on review sites (e.g. https://gotit.pub) until another preprint comes out to critique and improve on prior work.
The Case for arXiv (Being Fair)
I don’t want to be entirely one-sided here, because the alternative, i.e. returning to traditional journal timelines, is not better. In fact, I could argue it is not suitable for AI at this time (though I would disagree with myself on that latter point!)
Peer review has its own well-documented failure modes. It is slow, biased toward established labs and prestigious institutions, and has failed catastrophically to catch replication crises in fields like social psychology and biomedical research that used it faithfully. Peer review is a filter, not a guarantee.
The open-access aspect of arXiv is also genuinely democratizing. Researchers at institutions without expensive journal subscriptions can fully participate in the conversation. That matters.
And the AI community does exercise a form of informal community review. As I mentioned above, it’s pretty safe to say that preprints risk getting publicly scrutinized on social media. Competing labs will work to replicate (or fail to replicate) the work, and will be challenged by follow-up work. For code and results that can be independently reproduced, this is actually quite fast and sometimes more effective than formal review. DeepSeek-R1 is again instructive: within days of its preprint release, multiple groups were attempting to reproduce its results, flag discrepancies, and extend its methods. The stronger the hype behind a paper (remember that huge dive NVDA took after DeepSeek?!?) So, that review process is real, and seems to work… most of the time. It just happens in public, messily, over months, rather than privately before publication.
The limitation of that informal process is also real, though: it works well for claims that can be reproduced from public code and standard benchmarks. It performs poorly for claims that hinge on proprietary data, undisclosed training details, or subtle methodological choices not visible in the paper. Those claims can circulate unchallenged for a long time.
The Problem Is the Conflation
Here’s my actual concern, stated plainly: arXiv is enormously useful as a communication tool, but it has been mistaken for a validation tool.
When a paper citing dozens of unreviewed technical reports is itself cited as authoritative in another preprint, we are building an increasingly tall structure on an unverified foundation. For fast-moving engineering claims that get stress-tested by replication at competing labs, this is uncomfortable but arguably tolerable. For deeper scientific claims about what these models actually learn, how they generalize, and whether reported gains reflect genuine capability acquisition, it is a meaningful epistemic risk that the field has largely chosen to accept without much reflection.
What would be better? At minimum: more careful hedging when citing unreviewed work, especially in introductions and related-work sections where preprints often get laundered into settled background. Journals and conference proceedings could normalize explicitly flagging which cited works were unreviewed at time of publication. Science journalists covering AI results could routinely note preprint status the way they note funding sources. None of these are radical changes in the process. It just requires some agility.
I know, I know. Agility is to academia as oil is to water.
Regardless, the speed of AI research is genuinely exciting. But speed without validation is just noise that moves fast.
It’s a reminder for all of us to be cautious and critical of all new preprints. Maybe we should have been doing this with all new research anyway.