Randomization
We used a randomized controlled single-blinded design.
The film, the hotline card, the film and hotline card together,
or the music CD were placed in hard CD covers which were
then placed in sealed opaque envelopes consecutively numbered
based on a computer generated random list. All envelopes
looked and felt the same. Recruiters were blinded to
the content of envelopes. Each participant received the next
envelop in the series when she enrolled in the study