Repeat viewing has been the topic of occasional research for more than 20 years. Until the late 1980s, these studies suggested that repeat viewing was one of the more commonplace and stable of all television audience behaviors. As Goodhardt et al. (1987) noted:
The overall result is simple if perhaps surprising. For popular programmes only around one half-generally some 55%—of the people who see a regular programme one week also see the next episode of it in the following week. This was first noted in the UK in the late sixties. But it still remains true 20 years later and it also holds in the USA and other countries. (p. 51)
This norm of audience duplication offered programmers a yardstick for measuring program loyalty. More importantly, it allowed marketers to use simple models of reach and frequency to craft their media plans. By the end of the 1980s, however, dramatic changes in the television viewing environment and a new regime of commercial audience measurement combined to complicate what had once appeared to be a straightforward feature of audience behavior.