Table 2 Data collection of the X:IT study – timeline, instrument and source of data
From: Design of a school-based randomized trial to reduce smoking among 13 to 15-year olds, the X:IT study
| Â | Baseline | Intervention | Follow-up 1 | Intervention | Follow-up 2 | Intervention | Follow-up 3 |
|---|---|---|---|---|---|---|---|
| Â | September 2010 | Â | June 2011 | Â | June 2012 | Â | May 2013 |
Interventions schools | Questionnaires. Students start year 7 n = 2,380 |  | Questionnaires. Students end year 7 n = 2,202 | Observation and interviews about implementation of curriculum | Questionnaires. Students end year 8 n = 1,748 |  | Questionnaires. Students end year 9 n = 777 |
Control schools | Questionnaires. Students start year 7 n = 1,781 |  | Questionnaires. Students end year 7 n = 1,562 |  | Questionnaires. Students end year 8 n = 1,521 |  | Questionnaires. Students end year 9 n = 639 |
Students and parents |  | Smoke free contracts n = 3,046 |  | Smoke free contracts n = 1,731 |  | Smoke free contracts n = 1,089 |  |
Study coordinator at schools |  |  | Questionnaires n = 92 |  | Questionnaires n = 78 |  | Questionnaires n = 61 |
Study coordinator in municipalities |  |  | Questionnaires n = 17 |  |  |  | Questionnaires n = 17 |
Teachers at intervention schools | Â | Â | Questionnaires | Interviews about implementation of curriculum | Questionnaires | Â | Questionnaires |