This article originally appeared in the Huffington Post. Over the past five years, I’ve interviewed thousands of Silicon Valley entrepreneurs looking for co-founders. I’ve connected many of them who then went on to create thriving businesses. Among others, I’ve matched the brilliant pair who built the social platform Refresh, which LinkedIn acquired earlier this year. I’ve learned a lot from these interviews and from my own experience about what matters when looking for a co-founder. It boils down to: • Complementary skills and interests, • Similar appetite for risk, and • Compatible communication & control style. Sounds so simple! Turns out that finding a co-founder is harder than getting into Stanford (admission rate: 5%). To help you increase your odds, I’ve created a 10-question quiz that you can take and ask any potential co-founder to take. Click here to take it.