The results of recent studies, however, again suggest that participant
preference for e-technologies may influence how successful
different engagement and retention strategies might be. For example,
Rooke et al. [111] compared two studies that used telephone vs.
Internet-based delivery of a treatment for cannabis use disorder
and found that the telephone intervention had a significantly lower
dropout rate compared with the web-based study (38% vs. 46% respectively,
p b 0.01)