Measuring the impact of AI on experienced open-source developer productivity

Here's the full paper, which has a lot of details missing from the summary linked above: https://metr.org/Early_2025_AI_Experienced_OS_Devs_Study.pdf

My personal theory is that getting a significant productivity boost from LLM assistance and AI tools has a much steeper learning curve than most people expect.

This study had 16 participants, with a mix of previous exposure to AI tools - 56% of them had never used Cursor before, and the study was mainly about Cursor.

They then had those 16 participants work on issues (about 15 each), where each issue was randomly assigned a "you can use AI" v.s. "you can't use AI" rule.

So each developer worked on a mix of AI-tasks and no-AI-tasks during the study.

A quarter of the participants saw increased performance, 3/4 saw reduced performance.

One of the top performers for AI was also someone with the most previous Cursor experience. The paper acknowledges that here:

> However, we see positive speedup for the one developer who has more than 50 hours of Cursor experience, so it's plausible that there is a high skill ceiling for using Cursor, such that developers with significant experience see positive speedup.

My intuition here is that this study mainly demonstrated that the learning curve on AI-assisted development is high enough that asking developers to bake it into their existing workflows reduces their performance while they climb that learing curve.

Well, there are two possible interpretations here of 75% of participants (all of whom had some experience using LLMs) being slower using generative AI:

LLMs have a v. steep and long learning curve as you posit (though note the points from the paper authors in the other reply).

Current LLMs just are not as good as they are sold to be as a programming assistant and people consistently predict and self-report in the wrong direction on how useful they are.

> Current LLMs

One thing that happened here is that they aren't using current LLMs:

> Most issues were completed in February and March 2025, before models like Claude 4 Opus or Gemini 2.5 Pro were released.

That doesn't mean this study is bad! In fact, I'd be very curious to see it done again, but with newer models, to see if that has an impact.

> One thing that happened here is that they aren't using current LLMs

I've been hearing this for 2 years now

the previous model retroactively becomes total dogshit the moment a new one is released

convenient, isn't it?

Sorry, that’s not my take. I didn’t think these tools were useful until the latest set of models, that is, they crossed the threshold of usefulness to me.

Even then though, “technology gets better over time” shouldn’t be surprising, as it’s pretty common.

Do you really see a massive jump?

For context, I've been using AI, a mix of OpenAi + Claude, mainly for bashing out quick React stuff. For over a year now. Anything else it's generally rubbish and slower than working without. Though I still use it to rubber duck, so I'm still seeing the level of quality for backend.

I'd say they're only marginally better today than they were even 2 years ago.

Every time a new model comes out you get a bunch of people raving how great the new one is and I honestly can't really tell the difference. The only real difference is reasoning models actually slowed everything down, but now I see its reasoning. It's only useful because I often spot it leaving out important stuff from the final answer.

Yes. In January I would have told you AI tools are bullshit. Today I’m on the $200/month Claude Max plan.

As with anything, your miles may vary: I’m not here to tell anyone that thinks they still suck that their experience is invalid, but to me it’s been a pretty big swing.

Ok, I'll have to try it out then. I've got a side project I've 3/4 finished and will let it loose on it.

So are you using Claude Code via the max plan, Cursor, or what?

I think I'd definitely hit AI news exhaustion and was viewing people raving about this agentic stuff as yet more AI fanbois. I'd just continued using the AI separate as setting up a new IDE seemed like too much work for the fractional gains I'd been seeing.

I had a bad time with Cursor. I use Claude Code inside of VS: Code. You don't necessarily need Max, but you can spend a lot of money very quickly on API tokens, so I'd recommend to anyone trying, start with the $20/month one, no need to spend a ton of money just to try something out.

There is a skill gap, like, I think of it like vim: at first it slows you down, but then as you learn it, you end up speeding up. So you may also find that it doesn't really vibe with the way you work, even if I am having a good time with it. I know people who are great engineers who still don't like this stuff, just like I know ones that do too.