You need 10 reviews to build trust

Airbnb is a great example of how you can build trust with simple design elements. The whole review system they have created is what makes people come out of the idea « It’s weird to go to a stranger home ». They do that just by showing you that other people did have a good experience. We would think that the correlation between a number of reviews and trust is linear. The more you have reviews, the bigger the trust. In fact, it’s more like a tipping point. This means that before a certain number of reviews the trust isn’t that big. And after a certain number of reviews you have trust and can’t build more trust. In a study, Airbnb made with Stanford university they exactly discovered that.

«If you’ve got less than three reviews, nothing changes. But if you’ve got more than 10, everything changes.» — Joe Gebbia, co-founder of Airbnb
Image from the Airbnb engineering blog

What this shows us is that to build trust, there is a minimal set of elements needed. Once you reach them, trust can exist. You don’t need to work more and more and more on it. Of course, you can, but you already have the minimal base needed to make people feel well.

The Airbnb example also shows that the way you design a service can have a huge impact on how people are willing to use it. As Joe Gebbia says it, thought good design we can help people go over their fears:

The right design can actually help us overcome one of our most deeply rooted biases.