Mathew PaquetPlaybook · 4 min read
The 90-Day New Hire Ladder
What a new hire does each week for their first 90 days when AI handles the routine work, so they still build the judgment that work used to teach.
In the jobs where AI can do the most tasks, experienced workers haven't lost any ground. People aged 22 to 25 in those same jobs have fallen 19% behind people their age in other jobs, per Stanford's Digital Economy Lab (August 2026). Not fired. Mostly, never hired.
A Harvard team, using résumés from about 65 million workers, found junior employment fell about 9% within six quarters at firms that built generative AI into their work. The tasks AI can do started disappearing from junior job postings: first drafts, data cleanup, meeting notes, the weekly report, the first pass at the code.
Nobody hired a junior for the quality of their first draft. The draft was the excuse.The real product was the person: a year of doing small things badly, getting corrected by someone better, and slowly learning why. That's my read. Take the tasks away and the job looks cheaper, but the training leaves with them. In a June 2026 BCG survey of 70 executives, 53% already see junior people developing more slowly.
Economists at Warwick and Oxford argue remote work explains the drop better than AI. Either way, one of them called the challenge "organisational rather than technological." Which means it's yours to fix. This plan is how.
One new hire's first month, built for AI doing the routine work.
When I choose [OPTION A]: [THE SIGNS I LOOK FOR]
When I choose [OPTION B]: [THE SIGNS I LOOK FOR]
The mistake a new person usually makes here: [MISTAKE]
How I check the AI's answer on this: [WHAT I LOOK AT]
Why week 3 matters: in Erik Brynjolfsson's study of 5,179 customer support agents, the researchers suggest the AI assistant spread the habits of the best agents to the newest ones. Your written reasoning is what you feed it.
Month 1 builds the rungs. Months 2 and 3 run the same four moves on bigger work, with less help each time. Agents two months in, with the AI, performed as well as agents six months in without it. Plan for that pace, and check it's real (section 4).
Senior time on the calendar: [DAYS AND TIMES]
The AI drafts they defend: [TYPE OF WORK]
The decisions the senior writes down: [DECISION 1] / [DECISION 2]
Result they own by week 4: [SMALL RESULT]
Result they own by week 10: [BIGGER RESULT]
Performing with a tool isn't the same as learning. In that BCG survey, 90% of leaders said they see people accepting AI output without questioning it. A junior who only accepts the answer never builds the judgment to check it.
Ask these four in the weekly review:
If they can't answer question 1, they're accepting, not learning. Go back to week 1 on that kind of work.
Most of the senior people you'll need in five years are somebody's junior today. Stop growing them and you pay later, hiring seniors from the companies that kept training theirs.
Sources
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Put two blocks a week on your newest hire's calendar next to a senior, and give them one AI first draft to defend tomorrow.
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