Managers account for 70 percent of the variance in engagement between business units, and that is a real, published figure. It is also the number that travels with "people do not leave companies, they leave managers". It measures engagement. It does not measure why anyone resigned.
The slogan is the most quoted sentence in human resources and has been in circulation for twenty-five years. The figure beside it answers a different question.
The 70 percent measures variance in engagement between units
The number comes from Gallup, and Gallup states it carefully. We went back to its own page explaining why great managers are so rare for the wording. Managers account for at least 70 percent of variance in employee engagement scores across business units.
Read that again with the qualifications intact.
Variance, not level. It says how much of the difference between business units is associated with the manager. It does not say how much of any individual's engagement the manager causes. In a company where every unit scored identically there would be no variance for a manager to account for, and the statistic would say nothing at all.
Across business units, not across individuals. The unit of analysis is a team, not a person.
Engagement, not turnover. The outcome is a score on an engagement instrument. Resignation is a different outcome with a different literature.
At least, and an estimate. Gallup's own phrasing includes both hedges.
The evidence base is large. The same page reports engagement measured across 27 million employees and more than 2.5 million work units over two decades. Scale is not the problem. The problem is that a statistic about variance in engagement scores between teams has been restated, step by step, as a statistic about why individuals resign.
Each restatement drops a qualification
The path from the research to the slide runs through four steps, each small enough to seem harmless.
- Managers account for at least 70 percent of the variance in engagement across business units.
- Managers account for 70 percent of engagement.
- Engagement drives retention, so managers drive retention.
- People leave managers, not companies.
Step two drops the variance framing and the unit-level framing. Step three swaps the outcome. Step four turns a partial association into an exclusive one. Only that last step is obviously wrong on its face, since nobody claims pay, workload, commute, career path and job security have no effect.
The slogan itself predates the statistic. It is generally traced to First, Break All the Rules, published in 1999 by Marcus Buckingham and Curt Coffman, both then at Gallup, and built on a large programme of interviews with managers. Interviews with managers are a legitimate source for a claim about what good managers do. They cannot establish why employees left. The employees who left were not the people being interviewed.
The underlying data has never been released
For a claim this widely repeated, one feature is unusual. The underlying data has never been released for independent examination.
Gallup is a commercial research firm and its engagement database is its principal asset. Keeping it private is commercially rational, and this is no accusation. But it means the most quoted quantitative claim in people management cannot be re-analysed, replicated or checked by anyone outside the firm that produced it. When a vendor's 70 percent sits on a slide next to a peer-reviewed effect size, the two are different kinds of object. The audience is rarely told which is which.
Turnover research puts attachment to the organisation first
Voluntary turnover has its own literature, independent of the engagement industry.
The most comprehensive recent synthesis is Rubenstein, Eberly, Lee and Mitchell's 2018 meta-analysis in Personnel Psychology. It pooled the research on the antecedents of voluntary employee turnover and updated the effect sizes for established and newer predictors. Among the correlations it reports are organisational commitment at −0.29, job security at −0.23 and engagement at −0.20, all in the expected direction. More of each, less quitting. It also finds that people who quit tend to do so earlier in their tenure, with a correlation of −0.27 between tenure and voluntary turnover across 117 studies.
These are modest correlations. No single variable explains much of turnover. And the strongest predictors in the list are attachments to the organisation and to the job. None of them is a measure of the immediate supervisor.
Managers are not irrelevant. A manager shapes workload, recognition, development, whether a promise about a promotion is kept, and much of what a job feels like day to day. All of those feed into commitment and engagement. The manager's contribution is real and mostly indirect. That finding is less quotable than the slogan and more useful.
Whether leavers cluster by manager can be checked inside one organisation
Taking the slogan literally leads to a specific and expensive response, with manager training as the retention strategy.
Manager development is worth doing, and the evidence behind it is reasonably strong, particularly at the junior end. But if a team is losing people because the pay bands have fallen behind the market, or because the role leads nowhere else, then training the manager answers a question nobody asked. It will be measured against a retention target it cannot move.
The manager population is also under strain, and that is independently documented. Manager engagement fell five points in a year, considerably faster than the workforce they manage. A retention strategy that asks that population to try harder has a problem whatever the 70 percent means.
What the published evidence cannot say is whether exit patterns in a given organisation cluster by manager or by something else. Most organisations can answer that from data they already hold, and it takes an afternoon. If leavers cluster under particular managers and not others, the slogan describes that organisation. If they cluster by grade, tenure band, location or function, it does not.
Common questions
Is it true that people leave managers, not companies? Not as stated. The figure usually cited measures how much of the variance in engagement scores between business units is associated with the manager. It is not a measure of why individuals resign, and no claim that one factor exclusively explains turnover survives contact with the research.
What does Gallup's 70 percent figure mean? That managers account for at least 70 percent of the variance in employee engagement scores across business units. It concerns differences between teams, it concerns engagement rather than turnover, and Gallup states it as an estimate.
Where does the phrase come from? It is generally traced to First, Break All the Rules by Marcus Buckingham and Curt Coffman, published in 1999 and based on Gallup interview research with managers.
What actually predicts voluntary turnover? A 2018 meta-analysis in Personnel Psychology reports organisational commitment at −0.29, job security at −0.23 and engagement at −0.20 among the predictors, along with a tendency for leavers to go earlier in their tenure. All the correlations are modest; turnover is not explained by any single factor.
Do managers matter for retention at all? Yes, largely indirectly. Managers shape workload, recognition, development and whether commitments are kept, all of which feed into the commitment and engagement measures that do predict turnover.
Can Gallup's engagement data be independently verified? No. The underlying database is not released for external review. That is commercially normal and it does mean the claim cannot be replicated outside the firm.
How should we work out whether managers are driving our turnover? Look at whether leavers cluster by manager or by something else, such as grade, tenure band, location or function. Most organisations can answer that from data they already hold.
Sources
- Gallup, Why Great Managers Are So Rare
- Gallup, State of the Global Workplace 2026 Report
- Rubenstein, Eberly, Lee & Mitchell (2018), Surveying the forest: A meta-analysis, moderator investigation, and future-oriented discussion of the antecedents of voluntary employee turnover, Personnel Psychology 71(1), 23-65
