The single best predictor of founder success we’ve seen, above all else, is raw determination. Across the 100+ successful founders we’ve interviewed, we identified 7 signals that measure this: (1) A history of being under-estimated. There was always someone early in their life who doubted them, whether that be a sibling, parent, teacher or colleague. (2) Lifelong iconoclasts. Never fit in with the group. Quirky tastes in hobbies, music, food that others find unusual. (3) Some evidence of prior failure. Whether that be previous companies, product launches or career pivots, they always failed at least once (and often multiple times). (4) Irrationally optimistic. If their lead engineer quits or a funding round fails or a key customer churns, they are never pessimistic and never lose hope. Always glass half full. (5) Lack of financial motives. The desire to succeed was never driven by money. Cash served as a scorecard and nothing else. (6) Funding struggles. Almost all struggled with early funding rounds, but did not give up in the face of capital scarcity. Lack of capital forced discipline. (7) Institutional rejection. They were almost always rejected by a top institution early in their career (sports team, school, college or company).