From a business perspective, the developer is the expert in lines of code and the assumption is that expertise should agree on the necessity of a line of code. To create lines of code that do not need to be there is akin to simply not doing your job in this perspective. The finished product should have X lines of code

so from a business standpoint, if equivalent expertise amongst staff is assumed then productivity comes down to lines of code created. Just like how you might measure productivity of a warehouse employee by the number of items moved per hour. Of course if someone just throws things across the warehouse or moves things that dont need to be moved they will maximize this metric, but that would be doing the job wrong - which is not a productivity measurement problem. though admittedly the incentive structures and competition make these things often related

the bigger issue to highlight, imo, is that the business side of things have no idea if coders are doing the job sufficiently well or not, and the lack of understanding is amplified by the reality that productivity contribution varies wildly per line, some requiring much more work to conjure than others. The person they need to rely on validate this difference per instance is the same person who is responsible for creating the lines. So there is a catch-22 on the business side. An unproductive employee can claim productivity no matter what the measurement is.

if the variance of work required per line could be understood by the business side then it could be managed for. I used to manage productivity metrics for a medical coding company, and some charts are more dense and harder to code than others. I did not know how to code a medical chart but I could still manage productivity by charts per hour while still understanding this caveat

the point isnt to use the productivity metric as a one stop shop for promoting and firing people but as a filter for attention, where all the middle of the pack stuff will more of less even out and not require too much direct attention. you then just need to get an understanding of how the average difficulty per item varies by product/project.

that said, maybe lines edited is still a step better - so that refactoring in a way that reduces the size of the codebase can still be seen as productive. 1 point for each line deleted and 1 point for each line added.

I understand that every line should be viewed as a liability, not an asset, but thats the job responsibility of the hired expert to figure out how many need to exist. its not the job of the business side of things to manage.

I wouldnt tell my foundation guys how much concrete to use, or my electrician how much wire to use, but if one team can handle more concrete per hour than another and they are both qualified professionals, it really doesnt seem unreasonable to start off conversations with an assumption that one is more productive than the other. Lazy people do exist everywhere, its usually a matter of magnitude of laziness between people more than it is a matter of actual full earnest capability

We're careful not to draw any conclusions from LoC. The fact is LoCs are higher, which by itself is interesting. This could be a good or bad thing depending on code quality, which itself varied wildly person-to-person and agent-to-agent.

That question has been baffling product managers, scrum masters, and C-suite assholes for decades. Along with how you measure engineering productivity.

Bad code can persist because nobody wants to touch it.

Unfortunately I’m not sure there are good metrics.

This is a good one, wish we had included it. I'd run some analysis on this a while ago and it was pretty interesting.

An interesting subtrend is that Devin and other full async agents write the highest proportion of code at the largest companies. Ticket-to-PR hasn't worked nearly as well for startups as it has for the F500.

Right? I want to see the problem ticket variance year over year with something to qualify the data if release velocity is more frequent.

Thanks! The first 4 charts as well as Chart 2.3 are all from our data!

We weren’t able to find a good quality measure. LLM-as-judge dint feel right. You’re correct that without that the data is interesting but not particular insightful.

I've seen code persist a long time because it is unmaintainable gloop that takes forever to understand and nobody is brave enough to rebuild it.

So no, I don't think persistence-through-time is a good metric. Probably better to look at cyclomatic complexity, and maybe for a given code path or module or class hierarchy, how many calls it makes within itself vs to things outside the hierarchy - some measure of how many files you need to jump between to understand it

I've seen code entropy as the suggested hueriatic to measure.

My experience with coding agents points into the other direction: It's mentally very taxing!

Usually, you have a lot of time to think on the side while coding on what to do next, strategize, etc. But if you work in small increments with an LLM agent, this time is reduced and you have to be ready for the next thing once one increment is done.

So I don't see this as an equalizer. Rather, those who can constantly push forward are getting much more than those who don't.

I'm effectively no longer typing code by hand: I decide what change I want to make and then prompt Claude Code to describe that change. Sometimes I'll have it figure out the fix too.

An example from earlier today: https://github.com/simonw/llm-gemini/commit/fa6d147f5cff9ea9...

That commit added 33 lines and removed 13 - so I'm already at a 20-lines-a-day level just from that one commit (and I shipped a few more plus a release of llm-gemini: https://github.com/simonw/llm-gemini/commits/a2bdec13e03ca8a...)

It took about 3.5 minutes. I started from this issue someone had filed against my repo:

Then I opened Claude Code and said:

  Run this command: uv run llm -m gemma-3-27b-it hi 

  Yes, fix that - the gemma models do not support media resolution

I ran "git diff", thought about the change it had made for a moment, then committed and pushed it.

Here's the full Claude Code transcript: https://gistpreview.github.io/?62d090551ff26676dfbe54d8eebbc...

I verified the fix myself by running:

  uv run llm -m gemma-3-27b-it hi

Here's a more detailed version of the transcript including timestamps, showing my first prompt at 10:01:13am and the final response at 10:04:55am. https://tools.simonwillison.net/claude-code-timeline?url=htt...

I built that claude-code-timeline application this morning too, and that thing is 2284 lines of code: https://github.com/simonw/tools/commits/main/claude-code-tim... - but that was much more of a vibe-coded thing, I hardly reviewed the code that was written at all and shipped it as soon as it appeared to work correctly. Since it's a standalone HTML file there's not too much that can go wrong if it has bugs in it.

Yes, mostly Python and JavaScript and SQL. I'm dabbling a little more with Go these days too.

Yeah, I don't get it. It's well know that "LOC" is not a good metric of developer productivity. But now that AI is writing those lines of code, it's fine as a metric?

Totally. I have dozens of "simple CLI tools" that I work on - and small plugins, and HTML+JavaScript utilities.

If I was hacking on the Linux kernel I would be delighted with myself for producing 40 lines of landed code in a single day.

I would consider feature complete with robust testing to be a great proxy for code quality. Specifically, that if a chunk of code is feature complete and well tested and now changing slowly, it means -- as far as I can tell -- that the abstractions contained are at least ok at modeling the problem domain.

I would expect code that continually changes and deprecates and creates new features is still looking for a good problem domain fit.

It's tricky, but one can assume that code written once and not touched in a while is good code (didn't cause any issues, performance is good enough, ecc).

I guess you can already derive this value if you sum the total line changed by all PRs and divide it by (SLOC end - SLOC start). Ideally it must be a value slightly greater than 1.

It depends on how well you vetted your sanples.

fyi: You headline with "cross-industry", lead with fancy engineering productivity graphics, then caption it with small print saying its from your internal team data. Unless I'm completely missing something, it comes of as a little misleading and disingenuous. Maybe intro with what your company does and your data collection approach.

Language like "productivity gains", "output" and "force multiplier" isn't neutral like you're claiming here, and does imply that the line count metric indicates value being delivered for the business.