A Scientologist is a person who adheres to the beliefs and practices of Scientology, a movement founded by L. Ron Hubbard in the mid-20th century. The term is used for individuals who participate in Scientology services or training offered by the Church of Scientology, whether as public members or as part of the organization's staff. Estimates of the number of Scientologists vary widely, with the Church claiming worldwide membership in the millions, while national censuses and independent surveys indicate global totals in the tens of thousands.