The participants were chosen in an attempt to represent different social classes in Britain in the 1960s. Michael Apted states in the commentary track of the "42 Up" DVD that he was asked to find children at the extremes. Because the show was not originally intended to become a repeating series, no long-term contract was signed with the participants. According to Apted, participants in the subsequent programmes since "Seven Up!" have been paid a sum for their appearance in each film, as well as equal parts of any prize the film may win. Each subject is filmed in about two days and the interview itself takes more than six hours.