On April 13, 1970, two days into their journey to the moon, the crew of Apollo 13 heard a loud explosion. An oxygen tank had ruptured, crippling their spacecraft. NASA had the best engineers, protocols, and contingency plans in the world, but none of them accounted for this exact scenario. The mission plan—meticulously developed over years and years—was suddenly useless.
Instead of following the manual, NASA’s engineers worked with the astronauts to redesign their approach in real-time, using only the materials available on the spacecraft. The entire system had to adapt—and adapt fast. It’s said that what saved Apollo 13 wasn’t just expertise or control from the top, but the ability of the experts to reconfigure a complex system in the moment, based on the best available intelligence. This is what complexity looks like. This is how complex systems work.
Schools, like space missions, don’t run in neat, linear ways. And the more we treat them like machines, the more likely we are to fail when the unexpected happens (as the unexpected is wont to do).
Our ‘greatest shortcoming’?
The late physicist and educator, Al Bartlett, once1 said:
“The greatest shortcoming of the human race is our inability to understand the exponential function.”
What he meant was that our brains are wired to think in straight lines—to assume that when things grow, they do so in predictable, incremental ways.
I was thinking about this when reading
’ first piece about SEND earlier this week (‘The SEND crisis’). According to data from the NAO, the number of children in England with EHC plans has increased at an average rate of 10% each year since 2015.2Now, all things being equal, a 10% YoY increase sounds fairly manageable. Not ideal—but within the bounds of what most systems could reasonably tolerate. The problem is that when marginal increases like this compound over time, we very quickly find ourselves facing a challenge of another magnitude. For instance, this modest annual growth means that the number of children with EHC plans has more than doubled in nine years.
In complicated systems, we might expect that increasing the number of EHC plans by 10% each year would produce a proportional impact. But complex issues and systems don’t work like that.
What’s the difference between the two? Here’s an (imperfect) analogy:
A complicated system is like addition—you add more components, and while it gets harder to manage, the outputs are relatively predictable.
A complex system is more like multiplication—every new factor interacts with the others in ways that can’t always be foreseen, amplifying unpredictability.
Aptly, given the theme of this article, this analogy isn’t strictly accurate. A more precise way to think about the difference is that complicated systems scale arithmetically, while complex systems scale non-linearly—they grow and shift in ways that are unpredictable, sensitive to initial conditions, and sometimes even chaotic.
Bringing it back to schools
For school leaders, this distinction—between what’s complicated and complex—isn’t theoretical, it’s woven into the daily fabric of their work. School leaders wrestle with this misalignment every day.
Staffing shortages aren’t just a numbers game of missing teachers; they create cascading effects on workload, student experience, and retention cycles.
Behaviour issues don’t emerge in isolation but interact with mental health, attendance, and school culture in ways that can’t be solved with a single intervention.
Accountability pressures create unintended distortions—what gets measured (and rewarded) shapes cultures, sometimes, arguably, in ways that work against long-term improvement.
Parental engagement doesn’t just improve linearly with more communication; trust, relationships, and broader community dynamics influence how messages land.
Rising numbers of EHC plans don’t just mean more paperwork; they place increasing pressure on already stretched SEND teams, influence classroom dynamics, impact resource allocation, and create knock-on effects for staffing, timetabling, and whole-school inclusion strategies.
We might say that what school and trust leaders are experiencing right now is a ‘polycrisis’—a term coined by philosopher Edgar Morin in 1993 to describe a set of interconnected crises that amplify one another. Issues that might have been manageable in isolation—budget cuts, recruitment struggles, rising SEND needs, shifting expectations from policymakers—are colliding, making the system feel unmanageable.
That’s problematic.
The provocation of this piece, however, is that if this analysis is correct—if things haven’t always been thus and we really are dealing with proper complexity now—we need to accept that for what it is and approach it as such. When school leaders are pushed to ‘fix’ things themselves as if each issue were an isolated defect in a machine—rather than symptoms of a living, evolving system—we’re fighting a losing battle and need to change tack.
Why do we default to ‘fixing’ stuff?
There’s A Really Big answer to this question and I won’t even try to do it justice here. That said, at the very least, I think the following statement is true and would be part of a much bigger, better answer: Schools, like most organisations, have been conditioned to think in ‘cause-and-effect’, ‘input-output’, and ‘problem-solution’ frameworks. As I’ve outlined elsewhere, I think this is due in part to a ‘technocratic myopia’ induced by New Public Management approaches and an accountability system that rewards linearity: identify a gap, intervene, measure the impact, repeat.
While these linear approaches are so often helpful—and, full disclosure, I’m often the first person in any problem-solving exercise to grab one off the shelf—other approaches are available to us. Linear approaches are great in complicated, mechanistic systems but often fall short in complex ecological and human systems.
What is complexity anyway?
The algorithm gods bestowed another great gift unto me a few days ago:
’s article, Why we don't get complexity: Stafford Beer, 'requisite variety' and systems thinking. There, Hartnell offers up 7 rules of systems thinking:Parts combine to make new things.
Parts come together at different space or time scales.
Pathways (from the recombination of parts) become more complex over time.
We can look backwards at the doors we’ve passed through, but it’s hard to look forward (see: The Traitors, S3)
Systems pivot around stable attractors—until they don’t.
When a stable system experiences variation, it must adapt or die.
System parts have local and central elements.
Here’s what this list made me think about re: schools
Parts combine to make new things: Schools are constantly evolving ecosystems. Staffing structures, curriculum models, and pastoral systems all interact in ways that create new, often unexpected, realities.
Parts come together at different space or time scales: The classroom, the school, the trust, the wider policy environment—each operates on different timescales, meaning change at one level often disrupts another.
Pathways become more complex over time: The longer a school exists, the more embedded its rules, habits, and traditions become. What worked well five years ago may now be an obstacle to change.
We struggle to look forward: School and trust leaders habitually analyse data about the past but we lack the tools to forecast how small changes today will shape outcomes in five years.
Systems pivot around stable attractors—until they don’t: Schools can seem stable for years, then suddenly shift (think COVID, funding crises, demographic shifts). Leaders must recognise when an old system no longer serves them.
Adapt or die: Schools that treat problems as static will struggle. Leaders need to build adaptability into the DNA of their schools rather than relying on unyielding X-year strategic plans and reactive, one-off interventions.
Local and central intelligence: The best intelligence about what’s happening in a school doesn’t come from spreadsheets or inspection reports—it comes from the frontline: staff, students, and families.
So what? Is there another way?
There is. But it’s not very tidy. For those who crave clarity and love to simplify, simplify, simplify (🙋)—this is going to feel uncomfortable.
I think it’s fair to say that the dominant, prevailing model of school leadership is built around control, authority, and problem-solving. When I say this, I’m referring primarily to the governance and accountability structures. That is, over the last thirty years, we’ve seen a big shift away from the tripartite model (central government 🤝 local authority 🤝 school) towards a more centralised approach (DfE 👉 trust 👉 school). Interestingly, I think a similar thing could be said of our mindsets too; we think of leadership as decision-making, the leader being the one who spots the problem, applies the intervention, and measures the impact. For instance, the whole NPQ suite places great emphasis on the importance of effective implementation.
In a world of complicated systems, this makes perfect sense. But… But… But… If we accept that schools are complex adaptive systems rather than machines, then the role of a leader cannot be to dictate every outcome in advance. Those skills are still required in the system but school leadership needs to become more like navigation—a process of setting direction, sensing changes, and adapting in real-time.
This requires a few fundamental mindset shifts:
From controlling information to empowering local intelligence.
From rigid strategies to flexible principles.
From searching for ‘what works’ to designing for what can work in different contexts.
Some leaders will perceive this as a loss of control, but ultimately, it builds stronger, more resilient organisations and expands their capacity to do great work.
These shifts might not look like much to us on paper but they do feel uncomfortable for many in practice. Not least because most of us have been trained to believe that leadership is about certainty—about having the answers, not admitting uncertainty. But in complex systems, the best leaders aren’t those who control the most, but those who create the conditions for adaptation.
Remember, NASA didn’t save Apollo 13 because they had the right plan. They saved it because they built a system capable of adapting when the plan failed.
Some final thoughts
We’re talking about complexity a lot in education at the moment. Broadly speaking, I’m encouraged by this because I think that awareness alone is engendering greater empathy, curiosity and humility in the profession. But it’s not enough. We need to alter how we lead to produce the change we want. This means that the most effective school leaders won’t be the ones with the best ‘fixes’, they’ll be the ones who:
✅ Design for adaptability. Their schools won’t just have improvement plans; they will have mechanisms for constant learning—learning ways to continually sense what’s working with the ability to adjust course mid-flight.
✅ Decentralise intelligence. They’ll acknowledge that the best information about what’s working in a school doesn’t sit at the top or even in the middle—it lives at the edges, in the day-to-day experiences of students, teachers, and families. School leaders in these schools will be adept at pulling insights from the frontlines, not just pushing policies from the centre.
✅ Make peace with uncertainty. This is the hardest shift of all. It requires letting go of the fantasy that complex problems can be solved with simple, universal interventions. The best leaders will embrace trial and error, they will get comfortable learning in the open, and accept that success will rarely be linear.
Because while schools aren’t moon missions, the lesson from Apollo 13 still holds: when reality doesn’t match the plan, we shouldn't cling to the plan—we should adapt the system, fast.
2015 is an important year because, as Thomas outlines in his article, it’s the year after the coalition government introduced the Children and Families Act which replaced the prevailing system of statements with education, health and care plans.