If AI Does the Junior Work, Where Do Senior Engineers Come From?

AI can now do a useful first pass at a lot of the work we used to give people early in their career. Small bugs, tests, tracing how existing code works. It gets through that sort of thing quickly, although somebody still needs to give it the right context and check what comes back.

So why hire as many juniors?

From a business point of view that looks like an easy efficiency right now. The problem is nobody starts out with the judgement we now say matters most.

I’ve spent more than twenty years in software, a lot of that time leading engineers. People get good by doing the work, having it reviewed, getting things wrong, fixing them, and seeing what happens when software meets real users. Seniority is not a function of time. It comes from having seen enough decisions play out.

If AI takes some of the work that used to give people those experiences, we need another deliberate way for them to build judgement. I’m not sure enough companies are thinking about that yet.

#The early warning is already there

On 12 August, the Stanford Digital Economy Lab published updated research using payroll data from ADP. It found that employment among 22 to 25-year-olds in highly AI-exposed occupations was about 19% below where it would have been if it had kept pace with employment among similarly aged workers in less-exposed occupations. The change appeared to be coming mainly from lower hiring rather than more people leaving those jobs.

That doesn’t prove AI caused it. The researchers are clear about that, and the figures cover more than software development.

But it does match the thing I’m worried about. Companies don’t need to make a big announcement that they are replacing junior developers with AI. They can just stop opening as many junior roles because the immediate need feels less obvious.

That decision makes sense one company at a time. Across the industry, it creates a problem.

We still need experienced engineers. People who understand systems, can challenge a requirement, and will take responsibility when something goes live. People who can spot when an answer looks convincing and is still wrong. Those skills come from practice. AI can support that practice. It cannot give somebody the experience of being accountable for a real decision.

#The junior role has to change

I don’t think the answer is keeping pointless work around so juniors have something to do. If AI can take the repetitive stuff, we should use it.

The junior role has to change, but it cannot become sitting there reviewing AI output. People still need to design, change, debug and operate real software. A first pass from AI is fine. The developer should still be able to explain what it does, why it fits the system, what could go wrong, and how they tested it.

Give them small but real pieces of work, then increase the responsibility as their judgement improves. Let them use AI. Don’t let the tool own the decision. They need to see production problems, hear why requirements change, and understand what happens after a feature has shipped.

This takes time from senior people. There is no clever way around that.

If every senior engineer is measured only on how much they deliver this month, mentoring somebody will always look inefficient. Tech debt grows the same way. That time has to be planned rather than squeezed in around delivery. The benefit arrives later, when that person can handle harder work without everything being passed upwards.

I don’t have a finished answer yet. I do think hiring fewer junior developers and hoping the senior market sorts itself out is too easy.

We still need to give people a way in, let them do real work, and spend time reviewing it. That is slower than asking AI.

It is also how people get good.