While there may be evidence that diversity leads to better decision making, this isn't it. It's a marketing piece for a company that sells a decision making co-working platform. Direct from the white paper:

"The study was able to measure when teams made better decisions by tracking how often the decision maker changed their mind based on the input of the team. This is presumed to be a better decision since the Cloverpop process ensures that decisions are well framed with clear goals, adequate information and multiple alternatives to avoid groupthink."

In other words, this study defines better decisions as ones which make their product relevant, which unless you're a Cloverpop marketing exec, probably isn't a good metric.