Generative AI is not going to build your engineering team for you

It’s easy to generate code, but not so easy to generate good code.

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Credit: Alexandra Francis

When I was 19 years old, I dropped out of college and moved to San Francisco. I had a job offer in hand to be a Unix sysadmin for Taos Consulting. However, before my first day of work I was lured away to a startup in the city, where I worked as a software engineer on mail subsystems.

I never questioned whether or not I could find work. Jobs were plentiful, and more importantly, hiring standards were very low. If you knew how to sling HTML or find your way around a command line, chances were you could find someone to pay you.

Was I some kind of genius, born with my hands on a computer keyboard? Assuredly not. I was homeschooled in the backwoods of Idaho. I didn’t touch a computer until I was sixteen and in college. I escaped to university on a classical performance piano scholarship, which I later traded in for a peripatetic series of nontechnical majors: classical Latin and Greek, musical theory, philosophy. Everything I knew about computers I learned on the job, doing sysadmin work for the university and CS departments.

In retrospect, I was so lucky to enter the industry when I did. It makes me blanch to think of what would have happened if I had come along a few years later. Every one of the ladders my friends and I took into the industry has long since vanished.

The software industry is growing up

To some extent, this is just what happens as an industry matures. The early days of any field are something of a Wild West, where the stakes are low, regulation nonexistent, and standards nascent. If you look at the early history of other industries—medicine, cinema, radio—the similarities are striking.

There is a magical moment with any young technology where the boundaries between roles are porous and opportunity can be seized by anyone who is motivated, curious, and willing to work their asses off.

It never lasts. It can’t; it shouldn’t. The amount of prerequisite knowledge and experience you must have before you can enter the industry swells precipitously. The stakes rise, the magnitude of the mission increases, the cost of mistakes soars. We develop certifications, trainings, standards, legal rites. We wrangle over whether or not software engineers are really engineers.

Software is an apprenticeship industry

Nowadays, you wouldn’t want a teenaged dropout like me to roll out of junior year and onto your pager rotation. The prerequisite knowledge you need to enter the industry has grown, the pace is faster, and the stakes are much higher, so you can no longer learn literally everything on the job, as I once did.

However, it’s not like you can learn everything you need to know at college either. A CS degree typically prepares you better for a life of computing research than life as a workaday software engineer. A more practical path into the industry may be a good coding bootcamp, with its emphasis on problem solving and learning a modern toolkit. In either case, you don’t so much learn “how to do the job” as you do “learn enough of the basics to understand and use the tools you need to use to learn the job.”

Software is an apprenticeship industry. You can’t learn to be a software engineer by reading books. You can only learn by doing…and doing, and doing, and doing some more. No matter what your education consists of, most learning happens on the job—period. And it never ends! Learning and teaching are lifelong practices; they have to be, the industry changes so fast.

It takes a solid seven-plus years to forge a competent software engineer. (Or as most job ladders would call it, a “senior software engineer”.) That’s many years of writing, reviewing, and deploying code every day, on a team alongside more experienced engineers. That’s just how long it seems to take.

What does it mean to be a “senior engineer”?

Here is where I often get some very indignant pushback to my timelines, e.g.:

“Seven years?! Pfft, it took me two years!”

“I was promoted to Senior Software Engineer in less than five years!”

Good for you. True, there is nothing magic about seven years. But it takes time and experience to mature into an experienced engineer, the kind who can anchor a team. More than that, it takes practice.

I think we have come to use “Senior Software Engineer” as shorthand for engineers who can ship code and be a net positive in terms of productivity, and I think that’s a huge mistake. It implies that less senior engineers must be a net negative in terms of productivity, which is untrue. And it elides the real nature of the work of software engineering, of which writing code is only a small part.

To me, being a senior engineer is not primarily a function of your ability to write code. It has far more to do with your ability to understand, maintain, explain, and manage a large body of software in production over time, as well as the ability to translate business needs into technical implementation. So much of the work is around crafting and curating these large, complex sociotechnical systems, and code is just one representation of these systems.

What does it mean to be a senior engineer? It means you have learned how to learn, first and foremost, and how to teach; how to hold these models in your head and reason about them, and how to maintain, extend, and operate these systems over time. It means you have good judgment, and instincts you can trust.

Which brings us to the matter of AI.

We need to stop cannibalizing our own future

It is really, really tough to get your first role as an engineer. I didn’t realize how hard it was until I watched my little sister (new grad, terrific grades, some hands on experience, fiendishly hard worker) struggle for nearly two years to land a real job in her field. That was a few years ago; anecdotally, it seems to have gotten even harder since then.

This past year, I have read a steady drip of articles about entry-level jobs in various industries being replaced by AI. Some of which absolutely have merit. Any job that consists of drudgery such as converting a document from one format to another, reading and summarizing a bunch of text, or replacing one set of icons with another, seems pretty obviously vulnerable. This doesn’t feel all that revolutionary to me, it’s just extending the existing boom in automation to cover textual material as well as mathy stuff.

Recently, however, a number of execs and so-called “thought leaders” in tech seem to have genuinely convinced themselves that generative AI is on the verge of replacing all the work done by junior engineers. I have read so many articles about how junior engineering work is being automated out of existence, or that the need for junior engineers is shriveling up. It has officially driven me bonkers.

All of this bespeaks a deep misunderstanding about what engineers actually do. By not hiring and training up junior engineers, we are cannibalizing our own future. We need to stop doing that.

Writing code is the easy part

People act like writing code is the hard part of software. It is not. It never has been, it never will be. Writing code is the easiest part of software engineering, and it’s getting easier by the day. The hard parts are what you do with that code—operating it, understanding it, extending it, and governing it over its entire lifecycle.

A junior engineer begins by learning how to write and debug lines, functions, and snippets of code. As you practice and progress towards being a senior engineer, you learn to compose systems out of software, and guide systems through waves of change and transformation.

Sociotechnical systems consist of software, tools, and people; understanding them requires familiarity with the interplay between software, users, production, infrastructure, and continuous changes over time. These systems are fantastically complex and subject to chaos, nondeterminism and emergent behaviors. If anyone claims to understand the system they are developing and operating, the system is either exceptionally small or (more likely) they don’t know enough to know what they don’t know. Code is easy, in other words, but systems are hard.

The present wave of generative AI tools has done a lot to help us generate lots of code, very fast. The easy parts are becoming even easier, at a truly remarkable pace. But it has not done a thing to aid in the work of managing, understanding, or operating that code. If anything, it has only made the hard jobs harder.

It’s easy to generate code, and hard to generate good code

If you read a lot of breathless think pieces, you may have a mental image of software engineers merrily crafting prompts for ChatGPT, or using Copilot to generate reams of code, then committing whatever emerges to GitHub and walking away. That does not resemble our reality.

The right way to think about tools like Copilot is more like a really fancy autocomplete or copy-paste function, or maybe like the unholy love child of Stack Overflow search results plus Google’s “I feel lucky”. You roll the dice, every time.

These tools are at their best when there’s already a parallel in the file, and you want to just copy-paste the thing with slight modifications. Or when you’re writing tests and you have a giant block of fairly repetitive YAML, and it repeats the pattern while inserting the right column and field names, like an automatic template.

However, you cannot trust generated code. I can’t emphasize this enough. AI-generated code always looks quite plausible, but even when it kind of “works”, it’s rarely congruent with your wants and needs. It will happily generate code that doesn’t parse or compile. It will make up variables, method names, function calls; it will hallucinate fields that don’t exist. Generated code will not follow your coding practices or conventions. It is not going to refactor or come up with intelligent abstractions for you. The more important, difficult or meaningful a piece of code is, the less likely you are to generate a usable artifact using AI.

You may save time by not having to type the code in from scratch, but you will need to step through the output line by line, revising as you go, before you can commit your code, let alone ship it to production. In many cases this will take as much or more time as it would take to simply write the code—especially these days, now that autocomplete has gotten so clever and sophisticated. It can be a LOT of work to bring AI-generated code into compliance and coherence with the rest of your codebase. It isn’t always worth the effort, quite frankly.

Generating code that can compile, execute, and pass a test suite isn’t especially hard; the hard part is crafting a code base that many people, teams, and successive generations of teams can navigate, mutate, and reason about for years to come.

How working engineers really use generative AI

So that’s the TLDR: you can generate a lot of code, really fast, but you can’t trust what comes out. At all. However, there are some use cases where generative AI consistently shines.

For example, it’s often easier to ask chatGPT to generate example code using unfamiliar APIs than by reading the API docs—the corpus was trained on repositories where the APIs are being used for real life workloads, after all.

Generative AI is also pretty good at producing code that is annoying or tedious to write, yet tightly scoped and easy to explain. The more predictable a scenario is, the better these tools are at writing the code for you. If what you need is effectively copy-paste with a template—any time you could generate the code you want using sed/awk or vi macros—generative AI is quite good at this.

It’s also very good at writing little functions for you to do things in unfamiliar languages or scenarios. If you have a snippet of Python code and you want the same thing in Java, but you don’t know Java, generative AI has got your back.

Again, remember, the odds are 50/50 that the result is completely made up. You always have to assume the results are incorrect until you can verify it by hand. But these tools can absolutely accelerate your work in countless ways.

Generative AI is a little bit like a junior engineer

One of the engineers I work with, Kent Quirk, describes generative AI as “an excitable junior engineer who types really fast”. I love that quote—it leaves an indelible mental image.

Generative AI is like a junior engineer in that you can’t roll their code off into production. You are responsible for it—legally, ethically, and practically. You still have to take the time to understand it, test it, instrument it, retrofit it stylistically and thematically to fit the rest of your code base, and ensure your teammates can understand and maintain it as well.

The analogy is a decent one, actually, but only if your code is disposable and self-contained, i.e. not meant to be integrated into a larger body of work, or to survive and be read or modified by others.

And hey—there are corners of the industry like this, where most of the code is write-only, throwaway code. There are agencies that spin out dozens of disposable apps per year, each written for a particular launch or marketing event and then left to wither on the vine. But that is not most software. Disposable code is rare; code that needs to work over the long term is the norm. Even when we think a piece of code will be disposable, we are often (urf) wrong.

But generative AI is not a member of your team

In that particular sense—generating code that you know is untrustworthy—GenAI is a bit like a junior engineer. But in every other way, the analogy fails. Because adding a person who writes code to your team is nothing like autogenerating code. That code could have come from anywhere—Stack Overflow, Copilot, whatever. You don’t know, and it doesn’t really matter. There’s no feedback loop, no person on the other end trying iteratively to learn and improve, and no impact to your team vibes or culture.

To state the supremely obvious: giving code review feedback to a junior engineer is not like editing generated code. Your effort is worth more when it is invested into someone else’s apprenticeship. It’s an opportunity to pass on the lessons you’ve learned in your own career. Even just the act of framing your feedback to explain and convey your message forces you to think through the problem in a more rigorous way, and has a way of helping you understand the material more deeply.

And adding a junior engineer to your team will immediately change team dynamics. It creates an environment where asking questions is normalized and encouraged, where teaching as well as learning is a constant. We’ll talk more about team dynamics in a moment.

The time you invest into helping a junior engineer level up can pay off remarkably quickly. Time flies. ☺️ When it comes to hiring, we tend to valorize senior engineers almost as much as we underestimate junior engineers. Neither stereotype is helpful.

We underestimate the cost of hiring seniors, and overestimate the cost of hiring juniors

People seem to think that once you hire a senior engineer, you can drop them onto a team and they will be immediately productive, while hiring a junior engineer will be a tax on team performance forever. Neither are true. Honestly, most of the work that most teams have to do is not that difficult, once it’s been broken down into its constituent parts. There’s plenty of room for lower level engineers to execute and flourish.

The grossly simplified perspective of your accountant goes something like this. “Why should we pay $100k for a junior engineer to slow things down, when we could pay $200k for a senior engineer to speed things up?” It makes no sense!

But you know and I know—every engineer who is paying attention should know—that’s not how engineering works. This is an apprenticeship industry, and productivity is defined by the output and carrying capacity of each team, not each person.

There are lots of ways a person can contribute to the overall velocity of a team, just like there are lots of ways a person can sap the energy out of a team or add friction and drag to everyone around them. These do not always correlate with the person’s level (at least not in the direction people tend to assume), and writing code is only one way.

Furthermore, every engineer you hire requires ramp time and investment before they can contribute. Hiring and training new engineers is a costly endeavor, no matter what level they are. It will take any senior engineer time to build up their mental model of the system, familiarize themselves with the tools and technology, and ramp up to speed. How long? It depends on how clean and organized the codebase is, past experience with your tools and technologies, how good you are at onboarding new engineers, and more, but likely around 6-9 months. They probably won’t reach cruising altitude for about a year.

Yes, the ramp will be longer for a junior engineer, and yes, it will require more investment from the team. But it’s not indefinite. Your junior engineer should be a net positive within roughly the same time frame, six months to a year, and they develop far more rapidly than more senior contributors. (Don’t forget, their contributions may vastly exceed the code they personally write.)

You do not have to be a senior engineer to add value

In terms of writing and shipping features, some of the most productive engineers I’ve ever known have been intermediate engineers. Not yet bogged down with all the meetings and curating and mentoring and advising and architecture, their calendars not yet pockmarked with interruptions, they can just build stuff. You see them put their headphones on first thing in the morning, write code all day, and cruise out the door in the evening having made incredible progress.

Intermediate engineers sit in this lovely, temporary state where they have gotten good enough at programming to be very productive, but they are still learning how to build and care for systems. All they do is write code, reams and reams of code.

And they’re energized…engaged. They’re having fun! They aren’t bored with writing a web form or a login page for the 1000th time. Everything is new, interesting, and exciting, which typically means they will do a better job, especially under the light direction of someone more experienced. Having intermediate engineers on a team is amazing. The only way you get them is by hiring junior engineers.

Having junior and intermediate engineers on a team is a shockingly good inoculation against overengineering and premature complexity. They don’t yet know enough about a problem to imagine all the infinite edge cases that need to be solved for. They help keep things simple, which is one of the hardest things to do.

The long term arguments for hiring junior engineers

If you ask, nearly everybody will wholeheartedly agree that hiring junior engineers is a good thing…and someone else should do it. This is because the long-term arguments for hiring junior engineers are compelling and fairly well understood.

  1. We need more senior engineers as an industry
  2. Somebody has to train them
  3. Junior engineers are cheaper
  4. They may add some much-needed diversity
  5. They are often very loyal to companies who invest in training them, and will stick around for years instead of job hopping
  6. Did we already mention that somebody needs to do it?

But long-term thinking is not a thing that companies, or capitalism in general, are typically great at. Framed this way, it makes it sound like you hire junior engineers as a selfless act of public service, at great cost to yourself. Companies are much more likely to want to externalize costs like those, which is how we got to where we are now.

The short term arguments for hiring junior engineers

However, there are at least as many arguments to be made for hiring junior engineers in the short term—selfish, hard-nosed, profitable reasons for why it benefits the team and the company to do so. You just have to shift your perspective slightly, from individuals to teams, to bring them into focus.

Let’s start here: hiring engineers is not a process of “picking the best person for the job”. Hiring engineers is about composing teams. The smallest unit of software ownership is not the individual, it’s the team. Only teams can own, build, and maintain a corpus of software. It is inherently a collaborative, cooperative activity.

If hiring engineers was about picking the “best people”, it would make sense to hire the most senior, experienced individual you can get for the money you have, because we are using “senior” and “experienced” as a proxy for “productivity”. (Questionable, but let’s not nitpick.) But the productivity of each individual is not what we should be optimizing for. The productivity of the team is all that matters.

And the best teams are always the ones with a diversity of strengths, perspectives, and levels of expertise. A monoculture can be spectacularly successful in the short term—it may even outperform a diverse team. But they do not scale well, and they do not adapt to unfamiliar challenges gracefully. The longer you wait to diversify, the harder it will be.

We need to hire junior engineers, and not just once, but consistently. We need to keep feeding the funnel from the bottom up. Junior engineers only stay junior for a couple years, and intermediate engineers turn into senior engineers. Super-senior engineers are not actually the best people to mentor junior engineers; the most effective mentor is usually someone just one level ahead, who vividly remembers what it was like in your shoes.

A healthy, high-performing team has a range of levels

A healthy team is an ecosystem. You wouldn’t staff a product engineering team with six DB experts and one mobile developer. Nor should you staff it with six staff+ engineers and one junior developer. A good team is composed of a range of skills and levels.

Have you ever been on a team packed exclusively with staff or principal engineers? It is not fun. That is not a high-functioning team. There is only so much high-level architecture and planning work to go around, there are only so many big decisions that need to be made. These engineers spend most of their time doing work that feels boring and repetitive, so they tend to over-engineer solutions and/or cut corners—sometimes at the same time. They compete for the “fun” stuff and find reasons to pick technical fights with each other. They chronically under-document and under-invest in the work that makes systems simple and tractable.

Teams that only have intermediate engineers (or beginners, or seniors, or whatever) will have different pathologies, but similar problems with contention and blind spots. The work itself has a wide range in complexity and difficulty—from simple, tightly scoped functions to tough, high-stakes architecture decisions. It makes sense for the people doing the work to occupy a similar range.

The best teams are ones where no one is bored, because every single person is working on something that challenges them and pushes their boundaries. The only way you can get this is by having a range of skill levels on the team.

The bottleneck we face is hiring, not training

The bottleneck we face now is not our ability to train up new junior engineers and give them skills. Nor is it about juniors learning to hustle harder; I see a lot of solid, well-meaning advice on this topic, but it’s not going to solve the problem. The bottleneck is giving them their first jobs. The bottleneck consists of companies who see them as a cost to externalize, not an investment in their—the company’s—future.

After their first job, an engineer can usually find work. But getting that first job, from what I can see, is murder. It is all but impossible—if you didn’t graduate from a top college, and you aren’t entering the feeder system of Big Tech, then it’s a roll of the dice, a question of luck or who has the best connections. It was rough before the chimera of “Generative AI can replace junior engineers” rose up from the swamp. And now…oof.

Where would you be, if you hadn’t gotten into tech when you did?

I know where I would be, and it is not here.

The internet loves to make fun of Boomers, the generation that famously coasted to college, home ownership, and retirement, then pulled the ladder up after them while mocking younger people as snowflakes. “Ok, Boomer” may be here to stay, but can we try to keep “Ok, Staff Engineer” from becoming a thing?

Nobody thinks we need fewer senior engineers

Lots of people seem to think we don’t need junior engineers, but nobody is arguing that we need fewer senior engineers, or will need fewer senior engineers in the foreseeable future.

I think it’s safe to assume that anything deterministic and automatable will eventually be automated. Software engineering is no different—we are ground zero! Of course we’re always looking for ways to automate and improve efficiency, as we should be.

But large software systems are unpredictable and nondeterministic, with emergent behaviors. The mere existence of users injects chaos into the system. Components can be automated, but complexity can only be managed.

Even if systems could be fully automated and managed by AI, the fact that we cannot understand how AI makes decisions is a huge, possibly insurmountable problem. Running your business on a system that humans can’t debug or understand seems like a risk so existential that no security, legal or finance team would ever sign off on it. Maybe some version of this future will come to pass, but it’s hard to see it from here. I would not bet my career or my company on it happening.

In the meantime, we still need more senior engineers. The only way to grow them is by fixing the funnel.

Should every company hire junior engineers?

No. You need to be able to set them up for success. Some factors that disqualify you from hiring junior engineers:

  • You have less than two years of runway
  • Your team is constantly in firefighting mode, or you have no slack in your system
  • You have no experienced managers, or you have bad managers, or no managers at all
  • You have no product roadmap
  • Nobody on your team has any interest in being their mentor or point person

The only thing worse than never hiring any junior engineers is hiring them into an awful experience where they can’t learn anything. (I wouldn’t set the bar quite as high as Cindy does in this article; while I understand where she’s coming from, it is so much easier to land your second job than your first job that I think most junior engineers would frankly choose a crappy first job over none at all.)

Being a fully distributed company isn’t a complete dealbreaker, but it does make things even harder. I would counsel junior engineers to seek out office jobs if at all possible. You learn so much faster when you can soak up casual conversations and technical chatter, and you lose that working from home. If you are a remote employer, know that you will need to work harder to compensate for this. I suggest connecting with others who have done this successfully (they exist!) for advice.

I also advise companies not to start by hiring a single junior engineer. If you’re going to hire one, hire two or three. Give them a cohort of peers, so it’s a little less intimidating and isolating.

Nobody is coming to fix our problems for us

I have come to believe that the only way this will ever change is if engineers and engineering managers across our industry take up this fight and make it personal.

Most of the places I know that do have a program for hiring and training entry level engineers, have it only because an engineer decided to fight for it. Engineers—sometimes engineering managers—were the ones who made the case and pushed for resources, then designed the program, interviewed and hired the junior engineers, and set them up with mentors. This is not an exotic project, it is well within the capabilities of most motivated, experienced engineers (and good for your career as well).

Finance isn’t going to lobby for this. Execs aren’t likely to step in. The more a person’s role inclines them to treat engineers like fungible resources, the less likely they are to understand why this matters.

AI is not coming to solve all our problems and write all our code for us—and even if it was, it wouldn’t matter. Writing code is but a sliver of what professional software engineers do, and arguably the easiest part. Only we have the context and the credibility to drive the changes we know form the bedrock for great teams and engineering excellence..

Great teams are how great engineers get made. Nobody knows this better than engineers and EMs. It’s time for us to make the case, and make it happen.

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