The basic gist of it is to give the llm some code to review and have it assign a grade multiple times. How much variance is there in the grade?
Then, prompt the same llm to be a "critical" reviewer with the same code multiple times. How much does that average critical grade change?
A low variance of grades across many generations and a low delta between "review this code" and "review this code with a critical eye" is a major positive signal for quality.
I've found that gpt-5.1 produces remarkably stable evaluations whereas Claude is all over the place. Furthermore, Claude will completely [and comically] change the tenor of its evaluation when asked to be critical whereas gpt-5.1 is directionally the same while tightening the screws.
You could also interpret these results to be a proxy for obsequiousness.
Edit: One major part of the eval i left out is "can an llm converge on an 'A'?" Let's say the llm gives the code a 6/10 (or B-). When you implement its suggestions and then provide the improved code in a new context, does the grade go up? Furthermore, can it eventually give itself an A, and consistently?
It's honestly impressive how good, stable, and convergent gpt-5.1 is. Claude is not great. I have yet to test it on Gemini 3.