Have you ever sat in a doctor's office for hours, despite having an appointment? Has a hotel turned down your reservation because it's full? Have you been bumped off a flight that you paid for? These are all symptoms of overbooking, a practice where businesses sell or book more than their capacity. So why do they do it? Nina Klietsch explains the math behind this frustrating practice. [Directed by Anton Trofimov, narrated by Addison Anderson].