Probability sample

A probability sample is a sample selected by a method based on the theory of probability (random process), that is, by a method involving knowledge of the likelihood of any unit being selected. OECD Source: United Nations Statistics Division, "Handbook of Vital Statistics Systems and Methods, Volume 1: Legal, Organisational and Technical Aspects", Studies in Methods, Series F, No. 35, United Nations, New York, 1991.