Both CSTADS/YSS and CTNS/CTADS/CTUMS data were used for the youth analysis: CSTADS/YSS data were used for youth in grades 7-9, who were approximately aged 12-14, and CTNS/CTADS/CTUMS was used for youth aged 15-19. Earlier waves of the CSTADS/YSS included students in grade 6 (CSTADS 2014-15 and earlier) or grades 5 and 6 (YSS 2006-07 and earlier); neither of these grades are included in this report, for purposes of comparability between survey waves. The more recent waves of the CSTADS/YSS (from 2006-07 onward) also included students in grades 10-12 (see https://www.canada.ca/en/health-canada/services/canadian-student-tobacco-alcohol-drugs-survey/2018-2019-detailed-tables.html), but these students were not included in the analysis due to their overlap in age with the CTNS/CTADS/CTUMS sample; CTNS/CTADS/CTUMS was selected as the data source for older youth since the sampling frame includes youth both in and out of school, whereas the CSTADS/YSS only samples youth who are attending school.
CSTADS/YSS and CTNS/CTADS/CTUMS data have been integrated where possible. However, differences in the questions asked on each survey and the timing of the surveys does not allow for parallel reporting of all measures. The most recent wave was 2020 for CTNS, and 2018-19 for CSTADS. The CSTADS/YSS runs on school years (data collection between September and June), while CTADS/CTUMS ran on calendar years (data collection from February to December), and CTNS runs for a shorter period around the end of the year (October 29 to December 17, 2019 for the 2019 CTNS, and from December 8, 2020 to January 16, 2021 for the 2020 CTNS). Data collected via the CSTADS/YSS (grades 7-9) are presented by grade rather than age, as the survey was school-based and sampling was done by grade. CTNS/CTADS/CTUMS is not school-based; data are presented by age.
The CSTADS/YSS, CTNS and CTADS/CTUMS each base their definition of a current smoker on different items: the CSTADS/YSS defines a current smoker as having smoked at least 100 cigarettes in his/her lifetime and smoked in the 30 days preceding the survey; CTADS/CTUMS defines a current smoker using their response to the question "At the present time do you smoke cigarettes every day, occasionally, or not at all?”; and, CTNS defines a current smoker as responding “Daily”, "Less than daily, but at least once a week” or “Less than once a week, but at least once in the past month" to the question, “During the past 30 days, how often did you smoke cigarettes?”.