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JKCalhoun

Is LMArena junk now?

I thought there was an aspect where you run two models on the same user-supplied query. Surely this can't be gamed?

> “optimized for conversationality”

I don't understand what that means - how it gives it an LMArena advantage.

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There are almost certainly ways to fine-tune the model in ways that make it perform better on the Arena, but perform worse in other benchmarks or in practice. Usually that's not a good trade-off. What's being suggested here is that Meta is running such a fine-tuned version on the Arena (and reporting those numbers) while running models with different fine-tuning on other benchmarks (and reporting those numbers), while giving the appearance that those are actually the same models.

It can be easily gamed. The users are self-selected, and they have zero incentive to be honest or rigorous or provide good responses. Some have incentives the opposite way. (There was a report of a prediction market user who said they had won a market on Gemini models by manipulating the votes; LMArena swore furiously there had definitely been no manipulation but was conspicuously silent on any details.) And the release of more LMArena responses has shown that a lot of the user ratings are blatantly wrong: either they're basically fraudulent, or LMArena's current users are people whose ratings you should be optimizing against because they are so ignorant, lazy, and superficial.

At this point, when I look at the output from my Gemini-2.5-pro sessions, they are so high quality, and take so long to read, and check, and have an informed opinion on, I just can't trust the slapdash approach of LMArena in assuming that careless driveby maybe-didn't-even-read-the-responses-ain't-no-one-got-time-for-that-nerd-shit ratings mean much of anything. There have been red flags in the past and I've been taking them ever less seriously even as one of many benchmarks since early last year, but maybe this is the biggest backfire yet. And it's only going to get worse. At this rate, without major overhaul, you should take being #1 on LMArena seriously as useful and important news - as a reason to not use a model.

It's past time for LMArena people to sit down and have some thorough reflection on whether it is still worth running at all, and at what point they are doing more harm than good. No benchmark lives forever and it is normal and healthy to shut them down at some point after having been saturated, but some manage to live a lot longer than they should have...

I guess I can't really refute your experience or observations. But, just a single anecdotal point; I use the arena's voting feature quite a bit and I try really hard to vote on the "best" answer. I've got no clue if the majority of the voters put the same level of effort into it or not, but I figure that an honest and rigorous vote is the least I can do in return for a service provided to me free with no obnoxious ads. There's a nonzero incentive to do the right thing, but it's hard to say where it comes from.

As an aside, I like getting two responses from two models that I can compare against one another (and with the primary sources of truth that I know a priori). Not only does that help me sanity-check the responses somewhat, but I get to interact with new models that I wouldn't have otherwise had the opportunity to. Learning new stuff is good, and being earnest is good.

_nick

In the time it takes you to do one good vote, the low-taste slopmaxxers can do 10 (or 20...?).

LMArena was always junk. I work in this space and while the media takes it seriously most scientists don't.

Random people ask random stuff and then it measures how good they feel. This is only a worthwhile evaluation if you're Google or Meta or OpenAI and you need to make a chartbot that keeps people coming back. It doesn't measure anything else useful.

Conversation is a two-way street. A good conversation mechanic could elicit better interaction from the users and result in better answers. Stands to reason, anyway.

I hear AI news from time to time from the M5M in the US - and the only place I've ever seen "LMArena" is on HN and in the LM studio discord. At a ratio of 5:1 at least.

It's mentioned quite a bit in the LLM related subreddits.

Llama 1 derived models on it were beating gpt 3.5 by have less refusals.

In one of karpathys videos he said that he was a bit suspicious that the models that score the highest in LMarena aren't the ones that people use the most to solve actual day to day problems.

Tangent, but does anyone know why links to lmarena.ai are banned on Reddit, site-wide?

(Last I checked 1 month ago)

evidence for this assertion please? its highly unlikely and maybe a bug

I should have re-tested prior to posting. It is fixed now. I just tried posting a comment with the link and it was not [removed by reddit].

It was a really strange situation that lasted for months. Posts or comments with a direct link were removed like they were the worst of the worst.

I tried posting to r/bugs and it was downvoted immediately. I eventually contacted he lmarena folks, so maybe they resolved it with reddit.

theres just no mechanism to my knowledge to ban links sitewide, esp small sites (vs normies) like lmarena

It was crazy. I tested in many subs, using posts and comments. The only caveat is that I only tried in one Reddit account. However, I could post links to any other site in subs that allow such things.

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