Mass-Observation is a United Kingdom social research project; originally the name of an organisation which ran from 1937 to the mid-1960s, and was revived in 1981 at the University of Sussex.
Mass-Observation originally aimed to record everyday life in Britain through a panel of around 500 untrained volunteer observers who either maintained diaries or replied to open-ended questionnaires (known as directives). The organisation also paid investigators to anonymously record people's conversation and behaviour at work, on the street and at various public occasions, including public meetings and sporting and religious events.