p-value of 7.9% — so very close to statistical significance.

the p-value for GPT-4.1 having a win rate of at least 49% is 4.92%, so we can say conclusively that GPT-4.1 is at least (essentially) evenly matched with Claude Sonnet 3.7, if not better.

Given that Claude Sonnet 3.7 has been generally considered to be the best (non-reasoning) model for coding, and given that GPT-4.1 is substantially cheaper ($2/million input, $8/million output vs. $3/million input, $15/million output), I think it's safe to say that this is significant news, although not a game changer

I make it 8.9% with a binomial test[0]. I rounded that to 10%, because any more precision than that was not justified.

Specifically, the results from the blog post are impossible: with 200 samples, you can't possibly have the claimed 54.9/45.1 split of binary outcomes. Either they didn't actually make 200 tests but some other number, they didn't actually get the results they reported, or they did some kind of undocumented data munging like excluding all tied results. In any case, the uncertainty about the input data is larger than the uncertainty from the rounding.

[0] In R, binom.test(110, 200, 0.5, alternative="greater")