Hundreds of rigged votes can skew AI model rankings on Chatbot Arena, study finds

The generative AI revolution has turned into a global race, with mixtures of models from private companies and open-source initiatives all competing to become the most popular and powerful. Many choose to promote their prowess by demonstrating their performance on common tests and levels within regular rankings.

But the legitimacy of those rankings has been thrown into question as new research published in Cornell University’s preprint server arXiv shows it’s possible to rig a model’s results with just a few hundred votes.

“When we talk about large language models, their performance on benchmarks is very important,” says study author Tianyu Pang, a researcher at Sea AI Lab, a Singapore-based research group. It helps promote startups looking to tout the abilities of their models, “which makes some startups motivated to get or manipulate the benchmark,” he says.

To test whether manipulation of the rankings was possible, Pang and his colleagues looked at Chatbot Arena, a crowdsourced AI benchmarking platform developed by researchers at the University of California Berkeley and LMArena. On Chatbot Arena, users can state their preference for one chatbot’s output over the other when put through a battery of tests. The results of those votes feed into the wider rankings that the platform shares publicly, and which are often regarded as definitive.

But Pang and his colleagues identified that it’s possible to sway the ranking position of models with just a few hundred votes.  “We just need to take hundreds of new votes to improve a single ranking position,” he says. “The technique is very simple.”

While Chatbot Arena keeps the identities of its models secret when they’re pitted against one another, Pang and his colleagues trained a classifier to identify which model is being used based on its outputs, with a high accuracy level. “Then we can utilize the rating system to more efficiently improve the model ranking with the least number of new votes,” he explains.

The vote-rigging experiment was not tested on the live version of Chatbot Arena so as not to poison the results of the real website, but instead on historical data from the ranking platform. Despite this, Pang says that it’d be possible to do so in real life with the proper version of Chatbot Arena.

The team behind the ranking platform did not respond to Fast Company’s request for comment. Pang says his last contact with Chatbot Arena came in September 2024 (before he conducted the experiment), when he flagged the potential technique to manipulate the results. According to Pang, the Chatbot Arena team responded by recommending the researchers sandbox test the principle in the historical data. Pang says that Chatbot Arena does have multiple anti-cheating mechanisms in place to avoid flooding voting, but that they don’t mitigate against his team’s technique.

“From the user side, for now, we cannot make sure the rankings are reliable,” says Pang. “It’s the responsibility of the Chatbot Arena team to implement some anti-cheating mechanism to make sure the benchmark is the real level.”

https://www.fastcompany.com/91273226/rigged-votes-ai-model-rankings-chatbot-arena?partner=rss&utm_source=rss&utm_medium=feed&utm_campaign=rss+fastcompany&utm_content=rss

Created 3mo | Feb 6, 2025, 2:10:06 PM


Login to add comment

Other posts in this group

These 5 free AI-powered Chrome extensions make Gmail so much better

Email: It’s one of the more evil of the necessary evils. We all spend a significant chunk of our days wading through messages, to the point that it can feel like a never-ending task. Save us, arti

May 12, 2025, 6:20:05 AM | Fast company - tech
30 years ago, ‘Hackers’ and ‘The Net’ predicted the possibilities—and horrors—of internet life

Getting an email in the mid-’90s was kind of an event—somewhere between hearing an unexpected knock at the door and walking into your own surprise party. The white-hot novelty of electronic mail i

May 11, 2025, 11:40:05 AM | Fast company - tech
Uber is hedging its bets when it comes to robotaxis

Uber CEO Dara Khosrowshahi is enthusiastic about the company’s pilot with Waymo. In

May 10, 2025, 2:50:05 PM | Fast company - tech
Apple may radically change its iPhone release schedule. Here are 3 business-boosting reasons why

For well over a decade now, consumers have been used to new iPhones coming out in the fall, like clockwork. However, according to a series of reports, Apple may be planning to change its iPhone re

May 10, 2025, 10:20:04 AM | Fast company - tech
How Google can save you money the next time you book travel

Booking travel has become a bit of a game—especially if you want to get the best possible prices and avoid getting ripped off.

That’s because hotels and airlines have developed the lovel

May 10, 2025, 10:20:03 AM | Fast company - tech
Uber staff revolts over return-to-office mandate

Uber is facing internal staff unrest as it attempts to implement a three-day-per-week return to office (RTO) mandate and stricter sabbatical eligibility. 

An all-hands meeting late

May 10, 2025, 1:10:03 AM | Fast company - tech
Why ‘k’ is the most hated text message, according to science

A study has confirmed what we all suspected: “K” is officially the worst text you can send.

It might look harmless enough, but this single letter has the power to shut down a conversatio

May 9, 2025, 10:40:05 PM | Fast company - tech