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TLDR
AI coding assistants are making code feel more maintainable while simultaneously eroding engineers' confidence in their changes, with PR sizes growing 60% and change failure rates becoming more volatile. The promised 10x productivity gains remain elusive, with median velocity increases around 7.7% and top performers at 70% — far from the hype.
Key points
PR size increased from 44 to 72 lines on average over a year.
Change confidence dropped 6% with a simultaneous 4% rise in code maintainability perception.
Median velocity increase from AI is only 7.7%, with no organization achieving 2x productivity gains.
Morgan Stanley's DevGen AI agent saves 300,000 hours per year by automating legacy code interpretation.
Time savings from AI are similar between junior and senior engineers despite different usage levels.
Techniques
- Dora metrics
- cohort analysis
- AI measurement framework
- platform readiness assessment
- agent feedback loops
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Transcript (captions)
Uh I'm Justin Rio. I'm the deputy CTO at DX. I get to do a lot of our research around uh developer experience and its relation to developer productivity. And certainly over the last year, a lot of
that research has focused on AI's impact on the developer experience and basic aspects of productivity uh within an organization. Uh so we produce these quarterly reports, our our state of AI
and AI impact reports which looks at really a lot of raw data that we're able to get from our platform. Our platform is a researchback platform uh built from the same folks who worked on Dora
metrics and the space framework and the DevX framework. Uh and really at the end of the day it's a data gathering platform that can look at a lot of different trends across an organization
with you know how are we focusing on developer experience are we seeing outcomes and improvements with developer experience and certainly are we seeing outcomes with the way that we're using
AI in our workflows. This session is going to be a little bit different than the 345 session I think that's up in the leadership room later today which just looks at the raw data from our newest
report. It's a little bit of a preview. This is looking at more like organizational trends and how our workflow is changing and and things like that based on the data that we're
seeing. Uh so first things first, let's kind of look at what we're seeing in terms of the velocity impact. Now if anybody's familiar with looking at various velocity metrics like PR
throughput and deployment frequency like hopefully you understand the caveat that these metrics are not perfect. They are proxy metrics for understanding the way that work flows through an organization.
They're not fully representative of the value generation. We're going to look at some metrics that are closer to that as well. But let's just try to understand what this technology is doing in terms
of just the raw velocity metrics in the organization. So here's our Dora metric for deployment frequency. Who's familiar with Dora metrics? All right, most of you. Great. Um, so this is one of the,
you know, four key metrics that tries to understand directionally, you know, the speed of shipping work within an environment. And we're seeing it steadily increase. um it's tapering off
a little bit. I think there's reasons for that. Uh some of the surge that we saw early on was due to people shipping, you know, PRs more frequently and and things like that. Um so we're seeing
increases in this. This is one small part of the SDLC PDLC, right? This is like the creation uh of the PR to actually trying to deploy this into production. It doesn't tell us about
revert rates. It doesn't tell us about defect ratios. It doesn't tell us about change failure rate. It just tells us about how much stuff are we now kind of pushing out into production. But you
know the data is showing us that this number is steadily increasing. Okay. Um the trends vary a little bit across regions. Um we are seeing North America just sort of like trending up. We've
seen Europe actually pull back a little bit just in the last quarter. Um I think you know there's there's a number of reasons for that. I mean obviously the way work is done in these regions are
differently. the way that we can spend money on this technology and think about token spend is different, the regulation is different. Um, but if we just look at the through line in general, you know,
we still see improvements uh in in this one metric of deploy frequency even across various regions. We do just see some variance in those regions. Here's one that's kind of interesting
though. Uh, the perceived rate of delivery. How much faster do engineers feel in terms of what they're delivering? It's gone up a little bit. This number shows an increase of about
four and a halfish percent. Um, but given that that's a full year and given all the investment and cost and new spend on AI, it's interesting that this perceived rate has not stayed has not
kind of crept up a little bit more. especially when you look at some studies like obviously infamous flawed MER study if you're familiar with that study uh back in February they actually released
a follow-up to that study saying that some of the signals they gathered were sort of imperfect and they needed to rethink some of that but what was interesting was that in these 16
engineers that were part of that study small study flawed study uh the productivity went down by about 19% but the perception went up by about 20% so there was like a 40% spread in
perception of productivity versus actual ual productivity. But here when we look at this on more of an aggregate things interestingly stay uh sort of flat. All right. What about impact on quality
and and delivery? Right? So those are just kind of our speed our velocity metrics. But what is this actually doing to our software quality? Um the first metric we'll look at here is the Dora
change failure rate metric. And uh let me prepare you. Most of you are sitting down. It's very volatile the impact that we've seen on quality over this period of time. Each line on this graph
represents a single company that was part of this particular part of this study. And that line shows whether you've moved up in terms of your change failure rate or moved down in terms of
your change failure rate. You want to go down. You want to be on the bottom side of this graph. Uh but what's interesting is if you look at some of these top lines, you see people increasing as much
as 2%. Which doesn't sound like much until you realize that the industry benchmark is about 4%. So that means shipping potentially 50% more defects than we were shipping before. So you
really just want to understand what side of this graph you're on. You want to start measuring this stuff, right? Um this pattern exists without AI, by the way. This has a lot to do, it's not
purely causal with AI. A lot of this has to do with like your release pipeline, your automated testing, everything that's surrounding the way that you're releasing the code. The pattern remains
the same. The amplitude has changed as a result of AI. We always see this type of shift in volatility, but not usually to these extremes. And that's the AI effect that we're seeing right there. Here's a
really interesting one. These are two qualitative quant uh uh quality metrics uh that normally are sort of in sync with one another. Code maintainability, how how maintainable dovel developers
perceive the code to be in terms of making changes to it. That number has gone up almost 4% according to our data. By the way, we're looking at about 200,000 engineers in this study to
gather this data. The uh co the change confidence though, which traditionally we've seen closely associated with code maintainability. Hey, this code is maintainable. It's modular. It's easy to
modify. I feel good about the changes that I'm pushing into production. Nope. Our change confidence number has gone down 6%. This is really an interesting tension because it means like, okay,
agents and assistants are making it easier for me to understand and modify the code that's in front of me, but I trust the outputs less. I'm more afraid now of breaking things than I was a year
ago. So, it's an interesting psychological effect that we see here. And a lot of this is because PR size is measurably increasing. This is going to be one of the most important metrics
that we look at this year. Hasn't quite doubled, but look at that trajectory, right? This is over the same period of study about a year and we've seen PRs go from uh around 44 lines on average per
PR up to 72. Now there's there's a number of reasons for this. It's not just, you know, the likelihood that the way that these models work is that they're be being trained to output
relatively mediocre code. I've been writing code professionally since the late 90s. I remember when it was a great mark of a developer to be able to implement the same use case with as
little code as possible. Now, it's like, well, no, let's get the thing out. And, you know, the code that's being generated is going to be essentially mediocre because it's law of averages.
But on top of that, too, think about if you've got a build pipeline that takes 45 minutes or an hour to complete and now I've got AI generating functions for me instantly. Am I going to push four
different PRs with four different functions and wait 45 minutes or an hour or whatever that is per build or I'm just going to cram all that code into a single PR? Right? So there's multiple
reasons for this, but it really bears mentioning that like every extra line of code is a potential bug, a potential vulnerability. It's more to review. It makes the code less portable. So we need
to pay attention to this metric as well because we're also seeing this associated with perception of incremental delivery. I get to work on small incremental changes and this is
actually one of the lowest qualitative developer experience drivers that we've seen impacted over the last year. This number and this sentiment has gone down 10%. And incremental delivery is awful
is is as we've learned also very important for uh for the way that we try to deliver in a way that's easy to roll back uh and where we can understand and review the changes that are being pushed
through. Okay. Uh what about demographic differences? Uh what is different about AI impacts across like you know junior devs and stuff like that? Junior
engineers are using AI the most. This really should surprise nobody. anytime we have sort of a new leap again writing code professionally since the late 90s I'm a bit of an OG I'm on this journey
too but there's less to unlearn when you're coming into the industry right in many many cases you've already been working with this kind of stuff like right out of school and so you're more
likely to implement it uh when you actually start working now we've seen some other trends there too uh we have interesting ways of looking per use case at efficiency uh which I'll get into in
the second talk later today and one of those is looking at agent experience like literally we're we're asking agents about their experience working with humans. We're trying to figure out what
use cases uh are they working on and how many tokens did they spend. And definitely we also see a trend where the more junior developers for the same use case will spend more tokens than a more
senior developer on the same use case. And that's just a learning curve, right? Again, that should surprise nobody. But in terms of who's using it the most, we do see juniors using it the most.
However, despite that additional use, we see staff plus or more senior engineers saving about the same amount of time, right? And and burning less tokens. I want to make sure that that's kind of
clear too. So in terms of like raw time savings in the aggregate output of this, it's pretty flat between junior engineers who are using the tech more and staff engineers who have an easier
time spotting hallucinations, understanding the architecture around the changes they're making and things like that. Smaller companies lead in time savings.
Sure, you know, the release pipelines are going to be less complicated. You know, there's less overall complexity in the organization. uh that's going to uh lead to more time savings for a company
that already has less friction and has a little bit more agility to it than a larger company. What about measurement? How should we be even be thinking about measuring this
stuff? I mean, it bears mentioning that that measuring developer productivity and measuring developer experience was a challenge before AI and we we never completed that conversation before kind
of throwing accelerant on this. Right? So, this is still a difficult thing and I'd argue even more difficult to do now because it's confounded by several different aspects of of AI, but we're
all going to have to answer this question this year, right? Spent 10 million or way more if you come to my talk later today on tokens. Uh where's our 10x productivity?
When we're thinking about this stuff, it's important to bear in mind that we don't throw away what we're measuring, right? our foundational developer experience and developer productivity
metrics are still what matter the most, right? We want to understand how a AI is impacting these trusted metrics that we've already been looking at. Like we want to maybe look at cohorts of users.
We maybe want to take data from the API telemetry and things that come out of the tools and use that to understand who's using what and where. But we would only want to use those cohorts and look
at them comparatively across our foundational metrics. What is this actually doing to quality? What is this actually doing to speed? What is this doing to impact to the organization and
value generation? And so this is where our AI measurement framework comes from. I won't spend too much time on this. We have a big white paper available. Uh my colleague Anton
who's standing in the back of the room in the the white shirt will be able to hand out some hard copies of reports that we have after the talk that go into the way that we derive this methodology
and how to use it and think about it. Um it focuses on three key dimensions of measurement. So looking at utilization, our daily active users, weekly active users, that sort of thing. Uh it looks
at impact. So which metric should we be, you know, looking for moving the needle based on utilization? Uh as our utilization goes up, what do we hope to see in terms of impact to the business?
And then cost. It's a fair joke that we're 15 years after the last major hype cycle and we're still trying to figure out cloud cost, but the stuff is getting pretty expensive. We're going to have to
measure it. Um so you can think about this as a bit of a maturity curve as well. Most people start with utilization on the left. Just figuring out what's happening in the organization with the
tech, who's using it, what are they using, how often, and for what use cases. And then how do we then cross reference those to the impact metrics, the value generation, what we really
want to understand to know whether these investments are actually working, which is what we really want to figure out. This is just an example of how we might correlate such a thing. So you could
look at two separate cohorts of users and you could compare them across metrics like PR cycle time or PR size or push back and review. Right? So lots of uh the way to think about this again is
to right now separate cohorts and then look at how that plays out across these foundational productivity metrics that we've learned to trust. We also need to able be able to understand our
platform's readiness. I like to say that in 2024 we gave everybody a coding assistant. In 2025 we started building agents. Now, we're realizing that our infrastructure wasn't ready for any of
this. A lot of the vendors that are here are are are selling solutions that help you with this problem. Um, I think if you can measure your platform's AI readiness, you're going to have a much
better handle on how efficient you're going to be spending tokens and providing context to these agents. So, these are things like clear and accurate, well structured documentation,
data structures with straightforward relations, manageable modular code, reliable local CI and non-flaky test suites. If by the way any of this sounds familiar to you, it's because we used to
just call this good developer experience, right? But it turns out that what's good for humans is also good for agents. So we may finally paradoxically be making those investments that we
should have been making over the last couple of decades. We also want to understand the effectiveness of the way that we work with AI. And this is one way of doing that. What you're actually
seeing here is feedback, qualitative feedback coming back from agents telling us where they ran into issues with steering with the human. the the context that was provided for them, the the
feedback cycles that they had to go through. So, we're actually getting that data from the agents to try to figure out how effective our teams are at working with AI. And we can break this
down into use cases, which is very important, too. We want to understand which use cases are giving us the most efficient token spend. And again, moving the needle for value creation and
productivity within the business. Finally, the fifth trend, integrating across the SDLC and PDLC. Why would we want to do this? Because code generation was never the bottleneck in the first
place, right? Even if engineers are getting like 100% accurate instant code coming from the models, which they are not, you would still only be attacking anywhere from maybe 14 to 16% of the
overall value stream. So we need to think beyond that. Uh especially because right now the productivity gains that we are actually seeing are more modest than expected. Despite additional PR
throughput uh increases, our median increase in the study that we did from November to to 2024 to February this year only found about a median 7.7% increase in this velocity metric, a 13%
average, but even our top performers were in the 70% range. Nobody hit 2x, nobody hit 5x, nobody hit 10x. And that's because our time savings that come out of AI are still being
outweighed by other nonAI factors within our organization, right? Right? We might be saving a lot of time with AI and that's great. But if we're still eclipsing those time savings because of
meeting heavy days and context switching and other sources of interruption, the cumulative effects of the dev environment and friction in the way that we create software around the code, then
we're not attacking the bottleneck. And as Ellie Goldroat from the theory of constraints and the goal and uh inspire inspiration for the Phoenix project would tell us that an hour saved on
something that isn't the bottleneck is worthless. And so we need to find the bottleneck and fix the bottleneck. And that's what a lot of organizations are doing. Morgan Stanley has been really
public about their creation of the DevGen AI agent, which is an agent for interpreting legacy code like uh mainframe natural and cobalt. And I hate to admit Pearl. I've written a lot of
Pearl in my career, but it's legacy now. The agent actually creates PRDS to hand to engineers to get rid of that reverse engineering step. And it's saving Morgan Stanley about 300,000 hours a year right
now. Zapier is one of my favorite stories in AI right now. They have a whole agent ecosystem that they're using to deal with a lot of administrative tasks and overhead like daily standups
and things like that. They've reduced their standups by using a agent summaries and things like that in this ecosystem that they've built to two times a week as opposed to five times a
week. They're successfully onboarding engineers within about a twoe period which is really fast. Our industry benchmark for that is over a month usually. But my favorite part about this
story is that they're seeing about a 15% additional value creation per engineer. So they are hiring more than they have in the history of their entire company because they realize the truth here that
they're getting more capacity per single engineer. They're getting a better return on investment per single engineer and hiring more engineers will improve their competitive edge. This is the
right attitude. This is a throughput story. This is an increased innovative capacity story. This is not a headcount replacement story. Fair. uh they're automating about 3,000 of their code
reviews a week triggered off of a pull request and um they look at superficial stuff. They still need humans in the loop, but the initial superficial uh uh review that comes from the agent is all
part of the system of record. It stays in the PR comments and so the next engineer to actually perform the review will have an idea of what the agents already looked at. So it can save some
time. Finally, Spotify, if anybody remembers the Spotify model from DevOps, they were sort of the northstar for DevOps. uh they built an agent for S SRRES that will gather remediation steps
from runbooks and information and context about the incident and put all that together into SR communication channels so that when an incident occurs the S sur has uh immediate context and
doesn't have to go through multiple minutes of discovery uh to figure out how to solve the issue. So, if you want to dive deeper into this data, our Q2 report is coming out in just a few
weeks. Uh, but the Q1 report still has a lot of tidbits from this session in it. And if you subscribe to our newsletter or you come back to the website, by midish end of July, we'll have our Q2
report. And if you want to see a preview of that report, that's the talk that I'm giving later this afternoon. Thanks everybody for your time. I appreciate it.