Recruiting headteachers as inspectors assumes good people make good inspections. Fifty years of social psychology suggests it’s not that simple. In 1971, American psychologist Philip Zimbardo took two dozen psychologically healthy young men, flipped a coin, and made half of them prisoners and half of them guards in a mock jail beneath Stanford’s psychology department. The study was meant to run for two weeks. It was abandoned after six days, when the “guards” – ordinary students, selected for their normality – had become authoritarian and, in some cases, cruel. Zimbardo’s conclusion was that it wasn’t bad apples that spoiled the barrel – it was the barrel that spoiled the apples. Put decent people in a role that confers power, hand them a uniform and a script, and the role starts to do the thinking for them. The Stanford prison experiment has taken a battering in recent years. We now know Zimbardo coached his guards, that participants were performing what they thought was expected, and that the study would never pass an ethics committee today. But its central, more defensible insight has been replicated in subtler forms, concluding that behaviour is shaped less by character than by situation, role and institutional script. Ofsted recruitment Which brings us to Ofsted. The inspectorate is piloting the recruitment of groups of serving school and college leaders – drawn from trusts and school networks – to work as part-time inspectors, with the first cohorts trained this year. The logic, championed by chief inspector Martyn Oliver, is intuitive and appealing. Inspections will feel less adversarial if the person across the table has walked in your shoes – marked your books, survived your budget round, dealt with the rogue behaviour incident. Practitioners will bring empathy, credibility and current knowledge and, over time, relationships with the sector will duly start to heal. It is a theory of change built on the good-apple assumption. But Zimbardo’s barrel should give us pause. Consider what happens when a serving headteacher puts on the inspector’s lanyard. It is unreasonable to expect them to arrive as a colleague. They arrive with a framework, a deadline, an evidence base to assemble and a lead inspector to satisfy. For two days, they hold close to unilateral power over another leader’s career, reputation and – as the sector has known painfully since headteacher Ruth Perry’s death – wellbeing. Every structural feature of the encounter casts them as guard, not peer. The role comes with its own gravity, and empathy is not a fixed personal quality that travels with you into any situation. It is highly sensitive to the script you are handed. Zealous performance None of this is new. Serving and former school leaders have made up a large share of Ofsted’s inspection workforce for years. Ask heads who have been through a difficult inspection whether the presence of a fellow practitioner on the team softened the experience. Some will say yes. Many will tell you the practitioner-inspectors were the most exacting people in the room, perhaps because nothing proves you belong in the new role quite like performing it zealously. The early evidence on Ofsted’s wider reforms points the same way. An independent wellbeing review by the charity Education Support warned that the reforms do not reduce the pressure on leaders. Changing who inspects, without changing what inspection is, treats the symptom and leaves the situation intact. This doesn’t mean the pilot is worthless. Practitioner knowledge genuinely improves the accuracy of inspection. A head who has wrestled with a falling roll or a recruitment crisis reads a school differently, and often more fairly. And there is a version of this reform that could work, but it requires Ofsted to redesign the barrel, not just restock it. Collegial process That means encounters where the inspector’s incentives reward dialogue rather than verdict. Where practitioner-inspectors can retain their identity as colleagues because the process is collegial. Where the consequences of a bad day are proportionate enough that no one across the table holds career-ending power. As a MAT chief executive, I have a role in making this work. E-ACT has 20 colleagues on the training pilot – and we are thinking carefully about how we support our leaders in navigating this dual persona, to protect their mental wellbeing and support the quality of their inspection work. Zimbardo’s experiment ended, famously, not because he stopped it but because a graduate student, Christina Maslach, walked into the basement, saw what everyone inside had normalised, and said: what you are doing to these boys is wrong. Everyone inside the system – including Zimbardo himself, who had slipped into his role as “prison superintendent” – had lost the ability to see it. That is the real lesson for Ofsted. The danger is not that it will recruit the wrong people. It is that it will recruit exactly the right people, place them inside an unchanged system, and then mistake their presence for reform. Someone needs to keep asking what the barrel is doing to them and it will probably have to be someone standing outside it.