Sample
Parents of children aged 2–15 years across NSW who had
participated in a baseline random digit telephone survey
for the program and who agreed to be followed up at a
later date were eligible to participate in the study (n =
1,594). Parents in this cohort were randomly selected for a
series of repeat cross-sectional telephone surveys conducted
before and after each of the communication campaigns.
There were nine surveys in all corresponding to
five mass media campaigns that were implemented during
the program. The cohort was recycled from survey five
onwards (Figure 1).