AI assistants are not a new idea. They are the first real attempt to fix a problem management research documented seventy years ago and never actually solved for most people.
Every pitch for an AI assistant makes some version of the same claim: it will take the administrative weight off your day so you can focus on the work that actually matters. That claim is usually presented as new. It is not. It is the exact same claim that got made about executive secretaries, and it is backed by the same research, run three separate times across seven decades, always finding the same number.
The short version: a large and remarkably stable share of professional work, something close to 40 percent, is low-judgment administrative overhead rather than the work someone was actually hired to do. For most of the twentieth century, the only fix on offer was a personal secretary, and that fix was rationed almost entirely by seniority. AI assistants are the first attempt to offer that same relief to everyone else. Here is where that number comes from, and why the history matters for judging whether the new fix is real.
The first study
In 1951, a Swedish economist named Sune Carlson did something nobody had done before. He asked a group of managing directors to keep detailed diaries of their working days, logged in real time rather than reconstructed from memory afterward. The result, published as Executive Behaviour, is generally regarded as the first systematic empirical study of what managers actually do with their time, as opposed to what people assumed they did.
The picture that emerged was not flattering. Executive days turned out to be fragmented, reactive, and dominated by short bursts of low-level activity. Phone calls. Correspondence. Brief conversations. Interruptions. The romantic image of the executive locked away making weighty strategic decisions bore little resemblance to the diaries. Most of the day was consumed by administrative traffic that did not require an executive’s judgment at all, it just required someone competent to handle it.
Carlson’s book was not widely read at the time. It was sparse on conclusions and thin on theory. But the method survived. Two decades later, Henry Mintzberg ran a similar observational study and arrived at the same finding, dressed in more modern language. Managers do not spend their days thinking. They spend their days responding.
The finding keeps getting rediscovered
What is striking is not that this was found once. It is that it has been found repeatedly, in different decades, using different methods, on different populations of workers, and the number keeps coming back roughly the same.
In 2013, Julian Birkinshaw and Jordan Cohen ran a three year study of knowledge workers and published the results in Harvard Business Review under the title “Make Time for the Work That Matters.” Their headline finding: knowledge workers spend an average of 41 percent of their time on discretionary activities that offer little personal satisfaction and could be handled competently by someone else. Participants who went through a structured process to identify and shed that work cut desk work by roughly six hours a week and meeting time by two more.
Five years later, Harvard Business School’s Michael Porter and Nitin Nohria published the results of tracking 27 Fortune 500 CEOs for a full year, more than 60,000 hours of coded time-use data. It remains the most detailed public look at how chief executives actually spend their days. The finding was not that these people were lazy or undisciplined. It was that even at the very top of an organization, with every resource available to protect their time, a large share of it still got eaten by things that did not need a CEO to do them.
Three studies, seven decades apart, using diaries, surveys, and direct observation, converging on the same basic fact: a large and remarkably stable percentage of professional work is low-judgment administrative overhead. Not incompetence. Not poor discipline. Just the physics of running an organization, where information has to move, calendars have to align, and someone has to read the email before anyone can decide whether it matters.
Why the fix was always rationed
Here is the part of the story that gets skipped over. The research kept finding the same problem, but the solution it kept prescribing, dedicated administrative support, was never distributed according to who had the problem. It was distributed according to seniority.
A junior employee drowning in the same 41 percent of low-value work as a CEO simply absorbed it. There was no equivalent relief further down the org chart. And as email, shared calendars, and self-service scheduling tools spread through the 1990s and 2000s, even the people who had once had dedicated secretarial support increasingly lost it, on the theory that the tools themselves had closed the gap. The secretary and executive assistant roles contracted sharply. The underlying problem the research had documented did not contract with them. It just became something everyone quietly managed alone.
This is worth sitting with, because it means the historical relationship between “having administrative support” and “being more productive” was never really tested at scale. It was tested at the top of organizations, on people who already had every other advantage, and the results were treated as proof of a general principle that was never actually given the chance to apply generally.
What changes when the support is not rationed by rank
The research gives a fairly precise description of what kind of work is worth taking off someone’s plate: correspondence, scheduling, screening, routine drafting, information retrieval, status tracking. Not judgment work. Not relationship work. The mechanical layer underneath both of those things.
That is also, not coincidentally, close to the exact list of tasks that current AI tools are best at and are being adopted for first. Which suggests the honest way to think about AI assistants is not as a replacement for a human secretary, doing the same job with different hardware. It is closer to the first real attempt to deliver the same category of relief that Carlson’s executives had, to people who were never senior enough to be given it.
That reframe matters because it changes what the interesting question is. The old question, does an executive with a secretary outperform one without, was really a proxy for a different question that took seventy years to ask properly: how much of anyone’s professional capacity is being spent on work that has nothing to do with why they were hired, and what happens when that overhead gets pushed down toward zero for everyone, not just the people at the top of the org chart.
There is a genuine limit to the analogy, and it is worth naming rather than skating past. A human assistant carries judgment and institutional memory that took Carlson’s own subjects years to build with the people supporting them, knowing which call to interrupt a meeting for and which one to let go to voicemail. Whether that layer of judgment gets replicated, approximated, or simply left undone is not a question the old research can answer, because the old research was never testing for it. What it can tell us, with unusual consistency across seventy years of data, is the size and shape of the problem being solved. That part, at least, is no longer a mystery.