Determination. When we started, we thought we were looking for smart people, but it turned out that intelligence was not as important as we expected. If you imagine someone with 100 percent determination and 100 percent intelligence, you can discard a lot of intelligence before they stop succeeding. But if you start discarding determination, you very quickly get an ineffectual and perpetual grad student.

Y Combinator founder Paul Graham explains his decision in picking startups based not on ideas but on founders and their determination. Ideas can be trivial. Ideas can advance far beyond their original inception, but determination and persistence go a long way.

Paul Graham on intelligence vs determination when investing in people