Multistage area probability sample design involving three selection stages: (1) geographic areas or primary sampling units (PSUs), (2) schools (or linked groups of schools) within PSUs, and (3) students within sampled schools. Of the 72 PSUs, 8 were selected with certainty, 10 were selected with a probability of .50, and the remainder were selected with probability proportionate to the size of the 8th- or 10th- grade class. In schools with more than 350 students in the grade, a random sample of students or classes was drawn. In schools with less than 350 students in a grade, all students were asked to participate. Each school was asked to participate for two years so that each year one-half of the sample is replaced. Schools refusing participation were replaced with similar schools in terms of geographic location, size, and type of school (e.g., public, private/Catholic, private/non-Catholic). For the 8th-grade survey, schools with less than 20 8th graders were excluded from the sample. For the 10th-grade survey, schools with less than 25 10th graders were excluded. The participation rate among schools has been between 66 and 80 percent since the inception of the study.

on-site questionnaireTo protect the anonymity of respondents, all variables that could be used to identify individuals have been collapsed or recoded in the public use files. These modifications should not affect analytic uses of the public use files.Variables omitted from the Western region questionnaires are noted in each codebook.A user guide is provided with the study documentation. It contains two year-to-year cross-time question indices for the MTF 8th- and 10th-grade surveys. The first is sorted by question location and the second is sorted by subject area.MTF does not release detailed geography codes in its public use files because of the disclosure risk it would cause. The MTF sample is drawn to generate representative samples of the four Census Bureau regions of the country (Northeast, Midwest, South, and West), but it does not generate representative samples of smaller geographic areas such as states, counties, or cities. For additional information about data that is withheld from the public use files please contact MTF directly at mtfinformation@umich.edu.

These surveys of 8th- and 10th-grade students are part of a series that explores changes in important values, behaviors, and lifestyle orientations of contemporary American youth. Students in each grade are randomly assigned to complete one of four questionnaires, each with a different subset of topical questions but containing a set of "core" questions on demographics and drug use. There are more than 450 variables across the questionnaires. Drugs covered by this survey include amphetamines (stimulants), barbiturates (tranquilizers), other prescription drugs, tobacco, alcohol, inhalants, steroids, marijuana, hashish, LSD, hallucinogens, cocaine, crack, ecstasy, methamphetamine, and injection drugs such as heroin.

Each of the eight parts contains a weight variable, V5. They were originally varied by school but modified to protect respondent confidentiality. Use the weight variable for all analyses, the results of which will differ slightly from published data tables that used original data.

Datasets: DS0: Study-Level Files DS1: 8th-Grade Form 1 Data DS2: 8th-Grade Form 2 Data DS3: 8th-Grade Form 3 Data DS4: 8th-Grade Form 4 Data DS5: 10th-Grade Form 1 Data DS6: 10th-Grade Form 2 Data DS7: 10th-Grade Form 3 Data DS8: 10th-Grade Form 4 Data

Response Rates: The student response rates for the 2004 8th- and 10th-grade surveys were 89 percent and 88 percent, respectively.

Enrolled 8th- and 10th-grade students in the contiguous United States.