Behavioral science, translated into product decisions.

A four-arm RCT of 161 college students tested reminders, financial incentives, and anchoring for building physical activity habits. The winning combination pinned the new behavior to an existing routine and paid out only when the timing matched. The design lessons are specific.

A recent JMIR RCT isolated gamification as the only variable in a mHealth study. Here is what that design actually proves, what it doesn't, and what it means for product teams building behavior-change apps.

An umbrella review of 20 systematic reviews covering 224,135 participants found social support was the most consistently effective behavior change technique across health domains. It also found that adding more BCTs to a product doesn't make it more effective.

A micro-randomized trial of 566 health app users found that standard push notifications lose 11% of their effect when a user received one the day before. Novel messages don't habituate the same way. The implications for notification design are specific and actionable.

A 2025 Nature Human Behaviour meta-analysis of 89 RCTs found that social norms messaging has a near-zero effect on health behavior once publication bias is corrected. Here's what that means for teams building social features into health products.

A 2026 scoping review and realist synthesis maps how group chats drive (or don't drive) behavior change in digital health. The mechanisms are not what most product teams think.

A 5,419-person factorial RCT of six digital behavior-change components, what landed, what backfired, and what it means for product teams shipping behavior change software.

A meta-analysis of 92 RCTs and 16,728 participants found no association between persuasive design principles and either engagement or clinical outcomes. What that means if you ship behavior-change software.

A real-world analysis of 250 adults aged 65+ on the Perx Health app found 95% medication adherence and retention measured in years, not weeks. What that means for the way we design for older users.

A factorial RCT published April 2 tested six behavior change components on alcohol, diet, physical activity, and smoking. The winner is boring, and most product teams aren't shipping it.

A 52-study scoping review maps four ways product teams measure engagement, and why the most common one misses the actual problem.

Most health-tech products have a cliff around day 10. Here's what I've seen cause it, and why usability scores won't predict it.

An overview of 23 systematic reviews found that half of digital health interventions don't use an explicit behavioral framework, and it shows in the outcomes.

Action planning is one of the most-used behavior change techniques in health apps. Most implementations are broken. Here's what the research says, and what a working version actually looks like.

Most product teams treat COM-B as a training slide. Here's what it actually looks like when you apply it to one behavior, one product, one user.

What this blog is for, why I'm writing it, and the kinds of posts you'll see here. Short version: applied behavioral science for product teams who want rigor.