Recruitment of schools and adolescents into the Otago School Students Lifestyle Survey Two (OSSLS2) study. Not every class was invited into the study; the number of classes per school was dependent on the school year size at each school. This ranged from one class per year in smaller schools to four classes per year at larger schools. Reasons for exclusion from the final dataset included clicking patterns detected, consistently choosing contradictory options to similar questions or picking multiple unrealistic answer options.
Skidmore et al. Nutrition Journal 2013 12:128 doi:10.1186/1475-2891-12-128