The 11 to 16 Study was a school-based study of health and health behaviours which followed a cohort living in a predominantly urban area in and around Glasgow City.  They were recruited in 1994 during their final year of (mainstream) primary school (Scottish Primary 7) at the age of 11 and followed through the transition to secondary school until the end of statutory education (Scottish Secondary 4 - S4) at age 15 in 1999, with one intermediate contact in Secondary 2 (S2, aged 13).