SUBJECTS AND SAMPLING
In October 1992, before the start of the campaign, a baseline sample of the population in each region was interviewed to record demographics, smoking history, and attitudes to smoking. The smoking questions formed only part of the interview, which also covered other health related behaviours and attitudes. The interviews were conducted in the homes of those sampled using a structured questionnaire and lasted about 30 minutes. Attempts were made to re-interview the same respondents six and 18 months later, after the first and second phases of the campaign. On both occasions a similar structured question- naire was completed. A consortium of market research organisations conducted the sampling and interviewing. Boundary areas, where TV signals from adjacent regions overlap, were not sampled.