adolescents aged 16 to 18 years, we decided to adapt
the original planning, in order to avoid that the adolescents
in our intervention were legally allowed to buy alcoholic
drinks at baseline and were no longer allowed
to buy alcohol at the follow-up measurement. Deciding
to delay the baseline measurement till January 2014
after the new law was implemented, had consequences
for the follow-up measurement as well. As our study is
school based and a six months follow-up after baseline
would fall into the summer holidays of the schools, we
decided to do the primary follow-up a little earlier, after
four months. Because we are also interested in the effects
of the intervention after a longer time period we
also included a secondary eight-month follow-up after
the summer holiday. Unfortunately, a part of our target
group will then be graduated so we will not be able to
do the second follow-up in schools, but rather have to
reach the adolescents outside school.