First, the founder needs to have considerable intelligence, which Roberts says in “wide supply these days.” Second, the founder needs to have a sense of humility and the ability to listen. That’s because he’s observed that successful CEOs who have an ability to admit what they don’t know and will do what they can to learn.

“They need to be able to listen and sort,” Roberts said at Fortune’s Brainstorm Health conference on Tuesday.

The last piece of criteria for Roberts when evaluating an entrepreneur is that the founder needs to be seeing an “approach for a big market need.” But it’s not as simple as just going after a large market opportunity in healthcare.

“One mistake I’ve made is backing a company where there is a market need but the technology is not ready for prime time,” said Roberts. Roberts gave the example of a health company he’d backed who had created a new surgical tool to perform gastric surgery through the esophagus. He explained that the technology could have been game changing but the actual device was extremely expensive to make. “It just wasn’t simple,” he added.

Roberts added one more pattern he’s noticed with successful companies he’s backed. “Most of the companies were not successful on the first thing they started with,” he said. “It was the second or third thing that took off.”