Using our interactive charts
Given the high prevalence of marijuana use and major policy and legal changes in Washington, questions may arise around changes in use over time. To address marijuana use, estimates based on surveys are often used. The wording of survey questions is essential to interpretation and comparison and is often different across surveys and sometimes changes within a single survey over time. Other important factors include the age ranges included in an estimate, differential non-response, and the time of year for school-based surveys. Differences in these characteristics can contribute to different estimates of conceptually the same attitude or behavior. We compare and contrast surveys on important characteristics that may explain such different estimates here. In addition to question wording and other methodological differences, social attitudes and policy trends can induce change within surveys over time, as it becomes, for example, more acceptable to admit marijuana use.
Marijuana use among youth, whose brains are still developing, may cause learning and memory problems. Use is associated with poor grades in school, although the marijuana may not be an actual cause of poor school performance but rather a concomitant sign of other difficulties.
The Healthy Youth Survey asks students to complete surveys in Washington classrooms in the fall of even-numbered school years. Respondents, of course, comprise those actually in class on that day. A number of questions ask about marijuana use and attitudes towards marijuana. Among 8th graders in 2014, 21% reported marijuana was easy to get, 12% reported that 'adults don't think it's wrong', and 12% reported that 'friends don't think it's wrong'. These proportions increase to 53%, 20%, and 35% among 10th graders, and 66%, 27%, and 48% among 12th graders. Four in 10 8th graders, 61% of 10th graders, and 72% of seniors report that there is little or no risk from trying marijuana once or twice. The proportion reporting no or low risk from regular use has steadily increased from 2004 to 2014, from 13% to 20% among 8th graders, 17% to 34% of 10th graders, and 20% to 45% of 12th graders. It should be noted that in 2014 the wording for the risk from regular use question changed from 'smoking' to 'using' marijuana.
Two other major surveys of health behaviors among young people are the Monitoring the Future project (MTF) and the Youth Risk Behavior Surveillance System (or the Youth Risk Behavior Survey, YRBS). State-specific results are not available from MTF, and Washington state conducts its HYS in lieu of participating in YRBS. We directly compare results from these three surveys for 10th graders below.
Despite increases in perceived access and acceptability of use, actual reported use among Washington high school students has not increased. The figure below presents reported lifetime and past month use (results are similar for 12th and 8th graders). As with the regular use risk question above, the HYS question that assesses lifetime use changed from ‘smoked’ to ‘used’ in 2014. (The wording for the past month use question underwent a relatively minor change, with ‘weed’ replacing ‘grass’ as a synonym for marijuana.) In Washington, the rate of past month use is about 60% of the lifetime use rate (67% among 8th graders), which implies about 6 in 10 of high school students who have ever used marijuana are regular users if we assume the past month is a representative month.