ABSTRACT
This chapter deals with one kind of data - information on patterns of population turnover and stability - which is frequently used to ‘indicate’ a number of theoretically important concepts in the scientific study of social change. Information is also usually collected on the numbers who have been traced between the sources but who have, nevertheless, been recorded as having a different address in the two listings; usually some attempt is also made to trace the direction of movements. Problems connected with the reliability, validity and theoretical significance of this kind of information can be cast into a number of specific questions. The larger the community, however, the smaller will be the need; community size, indeed, by affecting the degree to which random effects are suppressed, is highly relevant to much of what follows. In differentiated societies a problem of lack of flexibility in social structure and production would also arise in our perfectly stable case.
