youth enrolled in school and are not representative of all people in this age group and (2) as with other self-report surveys, the extent of under- or overreporting of behaviors cannot be determined.
The YRBSS survey contains 14 questions about drug use. Self-report information is collected about lifetime, past-year, and past-month use of marijuana, cocaine, heroin, inhalants, methamphetamines, hallucinogens, steroids, and prescription drugs. In addition, there are questions about age of onset for marijuana, about injecting drug use, about drug use at last sexual intercourse, and about access to and use of drugs on school property. These questions measure the level, frequency, and circumstances surrounding youthful drug use, which research has found to be related to a variety of harmful outcomes—teen suicide, early unwanted pregnancy, school failure, delinquency, and transmission of sexually transmitted diseases, including HIV.
While they collect similar information on drug use prevalence and follow nearly identical protocols for administering their questionnaires, there are significant differences between the YRBSS and Monitoring the Future (MTF). The surveys have different foci. The YRBSS measures risk behaviors of which drug use is only a single example. MTF’s major focus with regard to risk behaviors historically has been on drugs, measuring trends in drug use, the levels of perceived risk, and the degree of personal disapproval associated with each drug.2 Attitude toward drugs has been shown to be particularly important in explaining trends in use (Johnston et al., 2000). The sample size for the MTF is roughly twice that for the YRBSS, and the MTF survey asks 100 questions on drug use compared with 14 for the YRBSS. The age range covered is similar but not identical: MTF collects data on 8th, 10th, and 12th graders, whereas the YRBSS samples students in grades 9–12. Both surveys collect drug use data on college students and young adults.
Although both surveys utilize a nationally representative sample of youth attending school, the surveys report substantially different prevalence rates for marijuana and cocaine use (see Table B.2). Prevalence rates measured by these surveys for other drugs also may differ. It is not clear whether sampling differences, reporting differences, or some other unknown factors are responsible for the variation in drug use found in these two surveys.