Really interesting updates to their 2025 experiment.

Repeat devs from the original experiment went from 0-40% slowdown to now -10-40% speedup - and METR estimates this as a 'lower-bound'

more devs saying they dont even want to do 50% of their work without AI, even for 50/hr

30-50% of devs decided not to submit certain tasks without AI, missing the tasks with the highest uplift

it also seems like there is a skill gap - repeat devs from the first study are more productive with ai tools than newly recruited ones with variable experience

overall it seems like the high preference for devs to use AI is actually hurting METR's ability to judge their speedup, due to a refusal to do tasks without it. imo this is indirectly quite supportive for ai coding's productivity claims.

The finding of the first study was people cannot judge their performance with these tools. So I don’t think the lack of individuals not willing to work without them is indicative of productivity improvements. I think it’s indicative of them being enjoyable to use.