Why a 4-minute wait is the magic number for Starbucks

Last month, Starbucks’s new CEO Brian Niccol announced his first steps in his big “Back to Starbucks” comeback plan. He promised a return of the third place and an almost contrarian focus on experience, complete with drinks served in ceramic mugs again. He admitted stores were too lightly staffed, and that Starbucks needed to wrestle back some control from an algorithm given the job of assigning head counts. And then he said Starbucks had to get faster—not generically or...