How behavioral science can boost your conversion rates

Behavioral scientist Kristen Berman argues that people often act against their own intentions, and that behavioral design, which blends psychology and economics, can help product teams close the gap between intent and action. She shares four case studies where small changes more than doubled or significantly lifted conversion: forced choice and goal gradient at Steady, the endowment effect at Livongo, rounding up payments at EarnUp, and day-one commitments at a credit union. Each case is tied to a specific psychological principle. She closes with five practical steps for applying behavioral design: literature review, picking a key behavior, mapping the decision environment, identifying the psychology at play, and running theory-based experiments. The piece matters because it shifts attention from what users say to what they do and why.

01Key takeaways

• Evaluate whether the immediate benefit of an action outweighs its friction, since every step carries a cost.
• Frame choices as accept or decline rather than allowing 'maybe later', which often makes acceptance more attractive.
• Use ownership language, such as 'claim' rather than 'join', to make offers feel already partly theirs.
• Lean into behaviors users already perform, then reduce the effort needed to do more of them.
• Define key behaviors with uncomfortable specificity, including timing, quantity, and actions, before designing interventions.
• Start with a literature review and behavioral mapping, then change one thing at a time in experiments to learn what works.

02Key sections

Why people don't act rationally

Berman introduces behavioral science as the study of how cognitive, emotional, and social factors shape decisions. She notes that many preventable outcomes stem from choices people make, so designing to fit psychology can help people do what they already want.

Immediate benefits and forced choice

Steady's bank-linkage step lost most users, and reframing the choice as accept or decline, then focusing on completing setup, lifted linkage substantially. The lesson is that the immediate benefit of acting should outweigh its friction.

Ownership and the endowment effect

Livongo doubled registrations by changing 'Join the program' to 'Claim your welcome kit,' making the offer feel already owned and a smaller ask.

Building on existing behavior

EarnUp's 'round up' prompt made extra debt payments easier by matching how people already mentally round numbers, raising overpayment rates by 40 percent over the baseline prompt.

Five behavioral design strategies

Berman outlines a practical process: review existing research, define a specific key behavior, map every decision step, identify the barriers and benefits at each step, and run single-variable experiments grounded in theory.

03From the post

“Q: I’m looking for ways to increase the conversion rate of our core flow. I’ve already read your post on conversion, and it was great, but do you have any other suggestions? I’ll be honest, I wasn’t sure what to do with your question when I first got it. But then, while catching up with my buddy Kristen Berman, I found my answer. Kristen co-founded a company called Irrational Labs, which helps companies and nonprofits understand and leverage behavioral economics to increase the health, wealth, and happiness of their users. This work often includes helping companies design product and features that drive user behavior change. In practice, this can mean spending a lot of time on improving conversion. While chatting with Kristen, she shared story after story of how they used a few basic principles of behavioral science to more than double conversion of a bunch of different products. I was blown away, and knew I had to get her to share her wisdom more broadly. After much cajoling, she agreed to write a guest post. Below, Kristen shares four…”

04Frameworks mentioned

Summary and takeaways written by PM Atlas; quotes are short excerpts. © the original author.