Understanding what makes your clients tick is just as essential as having a firm grasp on their likes and dislikes. Can personality tests like the Enneagram system help designers improve their business?

A funny thing happened to me when I started to research the Enneagram system. I started by looking around for fans, thinking it would be a difficult search, only to quickly find that I’m already close with several people who have been quietly obsessed with it for years. An interest in the Enneagram, I came to learn, is a bit like a fascination with cryptocurrency or a fondness for the Grateful Dead—a passion that stays slightly hidden from view until a fellow devotee comes along.

The first time I brought up the subject with a designer, I couched it in a lot of context: “Have you ever heard of this thing, it’s sort of like a personality test, and everyone is assigned a number. It’s called the Ennea—” I began. “I’m a Five,” she blurted out, laughing at her own enthusiasm. “Can you tell I’m kind of obsessed?”