Comparisons with previous data
The age range in 2015 was slightly younger than 2013 due to a two month extension to the fieldwork period in 2013 and a slight overrepresentation of 13 year olds in 2015. However, the 2002 and 2004 cohorts were older than the 2006-2015 waves due to the later fieldwork period. It is important to bear this in mind when analysing long term trends, as the previous surveys show that age plays an important role in the incidence of smoking, drinking and drug use (Table 4).
Table 4: Age profile comparison between 2013 and 2015
|12 years old||5%||5%|
|13 years old||42%||47%|
|14 years old||7%||7%|
|15 years old||43%||40%|
|16 years old or more||2%||2%|
As the surveys prior to 2002 were completed by pupils aged 11-15, comparisons need to be made with age groups rather than year groups. Where comparisons with earlier surveys are made, therefore, S2 and S4 pupils from SALSUS 2015 are compared with 13 year olds and 15 year olds respectively. For simplicity, S2 pupils are referred to as '13 year olds' and S4 pupils as '15 year olds' throughout the report.