Across 12 episodes of Problems Worth Solving, one theme keeps surfacing: prevention is moving from a programme to an organising principle. And that shift impacts the role of service design.

When we started the podcast, I didn't expect prevention to be a recurring theme. I thought we'd be talking mostly about transformation, AI, the mechanics of change inside large organisations. And we have. 

But underneath almost every conversation with public health leaders, charities, GPs, psychiatrists, digital directors, and surgeons, the same sentiment surfaces. Healthcare needs to change, and the shift upstream is no longer optional. What's more, the 10 Year Health Plan places this shift at the heart of strategy.

But if prevention becomes the organising principle, what does that mean for the way we design services?

A few things are becoming clear.

Prevention is a population problem, not a patient problem

Rachel Hope, NHS England's director of digital prevention services, made a point that has stayed with me. If you're treating illness, you're designing for a finite group: the people who show up. If you're preventing it, you're designing for everyone. All sixty-plus million of them.

That changes the design brief. A service for people who walk through a clinic door can rely on the clinic as its context. A service aimed at the whole population cannot. It has to reach people who don't identify as patients, don't think of themselves as being at risk, and have no particular reason to engage. 

GP Dr Shanker Vijay, talked about the "wider consultation" - the recognition that the ten-minute appointment is the smallest part of the relationship, and that the majority of it has to happen outside the surgery.

Designing for that is a different task from designing a booking journey or a patient dashboard. It means understanding health behaviours when someone’s not ill. It means designing for the person who’s never been identified as high-risk because they've never been measured. It means thinking about the service as something continuous, not episodic.

The people who need it most are the hardest to reach

A recurring observation across the conversations: the groups who would benefit most from preventive services are the ones least likely to engage with them. 

Dr David Chaney at Diabetes UK talked about stigma keeping people away from care: around half of people with diabetes skip at least one appointment, often because of how the condition is perceived or how they fear being treated. 

He also described a new initiative, Diagnosis Connect, where people newly diagnosed with type 2 diabetes receive a text signposting them to support at Diabetes UK. This recognises that support is not just about what's available, but when and how it reaches someone. 

He also talked about the shift in type 2 diabetes from a progressive, lifelong diagnosis to one where remission is possible, but only for the 25,000 people so far offered access to the NHS pathway. The design question there is not whether the intervention works, instead it's about how you reach the people it could help most.

This is a problem we've been wrestling with in our own work.

NHS Gloucestershire asked us to help rethink how young people access mental health support. The service we co-designed with young people - On Your Mind Glos - brought 80+ mental health services into a single tool, and crucially integrated SMS access for young people who don't have expensive data plans. In its first year it reached over 10,000 young people. The lesson wasn't about the technology, it was that equity has to be a starting point, not a feature added later.

Treatment works if it reaches the people who show up. Prevention only works if it reaches the people who don't. That means equity has to be integral to design, not added as a nice-to-have.

The relationship as the intervention

Problems Worth Solving interviews keep reminding me that good care depends on the relationship, as much as the intervention. Professor Jim McManus at Public Health Wales talked about how a single empathic consultation can shift someone's behaviour for years. Dr David Chaney described the first year after a diabetes diagnosis as the moment where everything is set — for good or ill — by the quality of the conversations that happen in it. Dr Lia Ali, a consultant psychiatrist, makes the case that the therapeutic relationship is itself a clinical tool, and that digital services need to be designed to support it rather than replace it.

For designers, this is a useful counterbalance to our instinct to optimise for efficiency. A shorter journey isn't always a better one. A self-service option isn't always what someone needs. Sometimes the design job is to protect the conditions under which a good conversation can happen - remove the things stopping it, rather than to automate it away.

Where this leaves us

None of this is a neat conclusion. The shift to prevention is hard, and the people leading it inside the NHS are doing the careful work of systemic change. What the podcast has clarified for me is that service design has a specific valuable contribution to make to that work - not in designing apps or pathways in isolation, but in helping systems think about population-scale services, equity as a starting point, and the relationships that carry care.

That's the work we want to do. It's also the work we're figuring out. If you're wrestling with the same questions, I'd love to hear what you're learning.