When we asked the referrers, the vast majority said it was because of a company's reputation and what we call "visible expertise." In fact, the visibility of a firm's expertise is the single most important factor in someone making a referral.
Many referrers became aware of a company's capabilities when a member of its team spoke at a conference or wrote blog posts and articles that demonstrated the firm's knowledge. In some cases, the company showcased a successful project on its website or otherwise publicly demonstrated its skills and knowledge. In other words, professionals made their expertise visible to the outside world.
Some types of visible expertise are more important than others, we found. According to an earlier study, which we conducted in 2014, the most common sources of expertise-based referrals are speaking engagements and blog posts.