PRIMER: MEDIA DEMOGRAPHICS

Description and measurement of audiences is an essential activity for any medium in which advertising is sold, the rates charged for time or space being related to--and justified by--the size and composition of the audience attracted. Over time the means of achieving these measurements have become increasingly precise and sophisticated in both the technology for data gathering (eg, the peoplemeter) and the subsequent statistical analysis.

The starting point is, of course, the entire target population, usually that of the country or region, which it is conventional to categ