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

I’ve been thinking about what happens to junior developers as AI gets better.

From a business point of view, the temptation is obvious. AI can now produce a useful first pass at a lot of the work often given to somebody early in their career. Small bugs, tests, tracing how existing code works. It can get 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?

Right now, that might look like an easy efficiency. The problem is that nobody starts with the judgement we now say matters most.

I’ve spent more than twenty years in software and a lot of that time leading engineers. People become good by doing the work, having it reviewed, getting things wrong, fixing them and seeing what happens when software meets real users.

They don’t become senior because enough time has passed. They become senior because they have seen enough decisions play out.

If AI removes some of the work that gives 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 who understand systems, can challenge a requirement, spot when an answer looks convincing but is wrong, and take responsibility when something goes live. Those skills come from practice. AI can support that practice, but 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 remove repetitive work, 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, but the developer should be able to explain what it does, why it fits the system, what could go wrong and how they tested it.

That probably means giving people small but real pieces of work, then increasing the responsibility as their judgement improves. Let them use AI, but don’t let the tool own the decision. Let them see production problems, hear why requirements change and understand what happens after a feature has been 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. 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.