The Associated Press-mtvU poll of college students was conducted Sept. 20-24. It was based on interviews of 2,207 undergraduate students at 40 randomly chosen four-year schools having at least 1,000 undergraduates. The survey was conducted for the AP and mtvU by Edison Research of Somerville, N.J., under the direction and supervision of AP's polling unit.
The sample of schools was selected using a stratified probability methodology. All colleges and universities were grouped into four geographic regions and sorted by the number of undergraduates with a probability selection based on the number of undergraduates at each college or university. To protect privacy, the schools where the poll was conducted are not being identified.
The students, age 18-24, were handed questionnaires by trained interviewers who were on each campus over a two-day interview period. Students were selected by a random, predefined method at campus student centers or other similar high-traffic locations chosen to ensure that a wide range of students were eligible to participate. Each student filled out the survey on a confidential form and then sealed it into an envelope to ensure confidentiality. Students were offered a $5 cash payment in return for their cooperation.
Colleges and universities that were primarily Internet-based were not included in the sample.
As is done routinely in surveys, results were weighted, or adjusted, to ensure that responses accurately reflect the population's makeup by factors such as the probability of selection for each college and university, by the differential response rate by male and female students, and to reflect the distribution of undergraduate students by geographic region of the country.
No more than one time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 3 percentage points from the answers that would be obtained if all eligible college students were polled.
There are other sources of potential error in polls, including the wording and order of questions.
The questions and results for this poll are available at http://surveys.ap.org.