Simon Willison’s Weblog

You also mentioned the whole Chatbot Arena thing, which I think is interesting and points to the challenge around how you do benchmarking. How do you know what models are good for which things?

One of the things we've generally tried to do over the last year is anchor more of our models in our Meta AI product north star use cases. The issue with open source benchmarks, and any given thing like the LM Arena stuff, is that they’re often skewed toward a very specific set of uses cases, which are often not actually  what any normal person does in your product. [...]

So we're trying to anchor our north star on the product value that people report to us, what they say that they want, and what their revealed preferences are, and using the experiences that we have. Sometimes these benchmarks just don't quite line up. I think a lot of them are quite easily gameable.

On the Arena you'll see stuff like Sonnet 3.7, which is a great model, and it's not near the top. It was relatively easy for our team to tune a version of Llama 4 Maverick that could be way at the top. But the version we released, the pure model, actually has no tuning for that at all, so it's further down. So you just need to be careful with some of these benchmarks. We're going to index primarily on the products.

— Mark Zuckerberg, on Dwarkesh Patel's podcast