As a 20-something computer engineer looking for a job in the 1990s, Igor Tulchinsky hit on an idea: Mail thousands of flattering letters to CEOs of companies believing one of them would land on the right desk. The tactic paid off when he scored a job as a trading strategist that set him on track to a successful career on Wall Street.

At WorldQuant LLC, a quantitative investment firm Mr. Tulchinsky founded in 2007, the same formula is at the core of the firm’s DNA. In searching for patterns in torrents of data coming out of...