Why has San Francisco’s startup scene generated so many hugely valuable companies over the past decade? That’s the question we asked over the past few weeks while analyzing San Francisco startup funding, exit, and unicorn creation data. After all, it’s not as if founders of Uber, Airbnb, Lyft, Dropbox and Twitter had to get office space within a couple of miles of each other. We hadn’t thought our data-centric approach would yield a clear recipe for success.