The first interaction is the intervention
Prevention has an engagement problem. The services most capable of reducing long-term pressure on health systems – smoking cessation, weight management, early mental health support, chronic condition prevention, are consistently underused by the people they were built for. Programmes that could shift outcomes sit underutilised. The gap between who a service could help and who it actually helps is one of the most costly and persistent failures in the sector.
The usual response is more information. Clearer statistics. Better explanations of risk. More guidance on next steps. The assumption is that if people understood what was at stake, they'd act.
But most people already know. What stops them isn't ignorance, it's ambivalence, anxiety, or the simple difficulty of turning intention into action. In prevention, especially, there's no acute symptom forcing the issue. Just the knowledge that doing something now might matter later. That's a harder problem than information can solve. Design is how you solve it.
The moment that matters most
When we built an AI-first smoking cessation service for a US-based digital health platform, we learned quickly that the first interaction carries disproportionate weight. Cessation is a decision remade continuously, under conditions of discomfort and competing impulses. What someone experiences at the point of entry shapes whether they treat the programme as genuine support, or another thing to defer.
We started by surfacing people's own reasons for change, in their own words, before anything as transactional as confirming details or setting a quit date. Subsequent interactions were then adapted to where each person actually was. Someone still weighing the decision needed something different from someone already committed, and the product responded to that.
The service was built iteratively, with each version informed by engagement data and user research. The result: a 90–98% open rate and sustained engagement over multiple weeks. Not because the content was good, though it was, but because the experience felt personally relevant from the very first moment.
Friction is the enemy of follow-through
Even when someone arrives motivated, taking the first step can exhaust that motivation before anything meaningful happens. In prevention, where the impulse to act is often fragile, a clunky registration flow or an interface that makes things feel harder than they need to be can end the relationship before it starts.
Working on The Body Coach app, users already understood that exercise matters, so the challenge was designing an initiation experience that didn't extinguish the motivation people arrived with. We removed unnecessary steps, reduced the number of exercises and recipes on offer, and made the first meaningful action feel achievable within minutes, starting with something as simple as telling us your fitness level.
Over 70% of users completed account setup and their first weekly activity, against an industry benchmark of retaining just 12–13% of users by day 7 after download. The app has quality content. But that number is explained by what happened before users ever reached it.
Both products were built through continuous iteration, watching where momentum stalled, and fixing it. The insights were compounded in ways a single design sprint couldn't have produced. With The Body Coach specifically, the data showed the first six weeks were decisive: get someone through that window and they were far more likely to stick.
Who gets left behind
Poorly designed onboarding experiences don't underperform equally.
The people most likely to push through a high-friction, anxiety-inducing first experience are those who already feel comfortable navigating complex systems. People with lower health literacy, greater anxiety around medical contexts, or historical reasons for distrust are far more likely to fall away. These are often the same populations where preventable conditions are most prevalent, and where early intervention would have the greatest impact.
Every design decision at the moment of first contact is quietly a decision about who the service actually works for. Reducing friction, using language that acknowledges emotional reality, building in genuine choice and pacing, these things determine whether a prevention service reaches the people it was commissioned to reach, or just the people who would have engaged anyway.
How you start is how you mean to go on
The first experience sets the emotional contract for everything that follows. An opening that feels impersonal or indifferent signals what the rest of the relationship will look like. One that feels considered and useful, even briefly, creates a foundation that every subsequent interaction can build on.
In prevention, that foundation has to sustain someone through something harder than acute need. It has to keep them engaged when nothing yet feels wrong, when the payoff is distant, and when there are a hundred easier things to do instead.
Onboarding in preventative healthcare is the beginning of that relationship. Treating it as a registration step squanders the moment most likely to matter.