Survivorship Bias & the Illusion of Success
Rethinking Boarding School Outcomes: a new Theory of Change to Guide our Work
Boarding schools have long been associated with elite outcomes and power. Prime Ministers, judges, medical consultants, CEOs, and other high-status professionals are often recognised by wealth, voice and bearing as being the successful products of Britain’s most hallowed boarding institutions. This visible success has helped cement a cultural narrative: boarding school produces strong, capable leaders.
However, this dominant perception may be shaped less by fact and figures, and more by a cognitive distortion that leads us to draw conclusions when we see a highly visible but non-representative subset of individuals - the survivorship bias. By making broad, sweeping assumptions that are based primarily on those few who appear to have succeeded, we risk overlooking the broader, and more complex, reality - that some of those who went do boarding school did not fare well, and indeed may have been detrimentally harmed by the experience.
What is Survivorship Bias?
World War Planes
Survivorship bias occurs when we focus on individuals or entities that have made it through a process, while ignoring those who did not.
A classic example dates back to World War II.
Losing plane after plane, the US Air Force needed to reinforce their fighter planes to keep more in the sky. Engineers were about to reinforce the red dotted areas that matched bullet holes on returning aircraft. Statistician Abraham Wald famously advised otherwise - the engineers were guilty of Survivorship Bias. His insights helped win the war.
Abraham Wald pointed out to the engineers that their data set only showed the Surviving planes, and excluded the planes that had not returned. All the hits in those ‘white’ locations typically resulted in the aircraft being lost. So it was the undamaged areas on the returning planes that indicated vulnerability - not the red dots of the bullets the planes survived.
The lesson is clear: drawing conclusions from the highly visible ‘survivors’ leads to incomplete and often misleading perceptions.
Applying Survivorship Bias to Boarding School Outcomes
The success of a relatively small group of boarding school alumni in politics, law, and finance is often interpreted as evidence of the system’s overall effectiveness. This is a textbook case of survivorship bias.
The individuals who reach public prominence represent a highly visible minority. They do not, and cannot, speak for the full spectrum of outcomes experienced by the wider population of former boarders. In relying on these the success narratives of a high profile few, we risk equating visibility with representativeness—and “success” with wellbeing.
We know the picture is more nuanced, but in the absence of robust longitudinal data, we cannot truly understand the extent to which boarders are equipped by their education to lead rich, successful lives, or how many fail to do so. Nor can we understand the ways in which those who fail to thrive are harmed, and what factors influence those outcomes.
Our research hub aims to measure the many different outcomes from boarding school - the good and the bad - so society can make sound, evidence-based judgements on the merits of choosing a boarding school education as a proxy for home.