Krølner et al. BMC Public Health 2012, 12:191 http://www.biomedcentral.com/1471-2458/12/191 Page 14 of 25 Random sample of municipalities assessed for eligibility (N=10) Replacement: Sampling of one extra municipality Replacement: Sampling of a new school within one municipality Excluded (N=1) Reason: ongoing school FV programme in all municipal schools Excluded (N=1) Reason: Declined to participate Random sample of 4 schools assessed for eligibility within each municipality (N=40) Cluster randomised (n= 40) Allocated to intervention group Allocated to control group N=20 schools with 1,175 eligible year 7 pupils N=20 schools with 1,114 eligible year 7 pupils Baseline surveys: Pupil response rates: Baseline surveys: Pupil response rates: Response rates of eligible pupils: N= 1,133 (96.4%) Response rates of eligible pupils: N= 1, 053 (94.5%) Exclusion of pupil questionnaires: Exclusion of pupil questionnaires: Sabotage of survey responses: N= 1 Not consent from parents: N= 11 Sabotage of survey responses: N= 2 Not consent from parents: N= 16 Included in baseline file: N= 1,121 (95.4%) Included in baseline file: N=1,035 (92.9%) Parent response rates of children with baseline questionnaire Parent response rates of children with baseline questionnaire Children with at least one parent questionnaire: Children with at least one parent questionnaire: N= 674 (60.1 %) N= 561 (54.2%) Principal response rates: N= 20 (100%) Principal response rates: N=20 (100%) Response rates from leisure time survey: Managers of sports clubs: N= 16 of 21 eligible (76.2%) Sports coaches: N= 57 of 93 eligible (61.3%) Managers of youth clubs: N= 12 of 18 eligible (66.7%) Figure 2 Flow diagram of sampling, recruitment, randomisation and participation in the Boost study. expected to significantly decrease proportions of pupils at intervention schools who felt out of energy, had diffi- culties in concentrating during class in school and who ate unhealthy food almost daily. Also, we expected significant positive changes in pupils’ well-being. By use of questionnaires to the school principals, we will mea- sure whether participation in the Boost project has initiated some environmental changes and capacity