“Engineering is easy. People are hard.” This well-known line from Bill Coughran, a partner at Sequoia Capital who cut his teeth at Bell Labs and was later an executive at Google, recognized that most tech startup founders believe that three factors will make or break their success: technology, market fit, and sufficient capital. But this widely-held assumption ignores another key challenge. According to a piece of classic research from the Harvard Business School and McKinsey & Company, 65% of new ventures fail because of people issues — and specifically issues with senior executives. This and another recent study align with our experience: it’s not flawed technology, a misguided product, or a lack of cash that causes most failures among new ventures; it’s an inability to get the right team on board and collaborating effectively.