By Howell Wechsler
05/18/04 -- The Youth Risk Behavior Survey (YRBS) monitors six categories of priority health-risk behaviors among high school students.
These behaviors contribute to unintentional injuries and violence; tobacco use; alcohol and other drug use; sexual behaviors that can lead to unintended pregnancy and sexually transmitted diseases; unhealthy dietary behaviors; and physical inactivity.
The Centers for Disease Control and Prevention (CDC) began administering the YRBS in 1991 on a biennial basis to a nationally representative sample of students in grades 9-12.
In addition, most states, about 18 large schools districts, and five U.S. territories administer the YRBS on a similar timeline as part of their cooperative agreement with CDC.
More than 1.2 million students in public and private high schools have completed a YRBS. States and districts use YRBS data to prioritize health education and health promotion goals, support curricula or program modifications, support legislation that promotes health, and seek funding for new health-related initiatives.
One of the biggest questions school staff and parents often ask CDC about the YRBS is whether students answer the sensitive survey questions truthfully. While a few students probably do not answer the YRBS honestly, most students tell the truth. CDC's belief that students tell the truth is based on the following evidence.
• Psychometric studies. CDC and non-CDC researchers have conducted a series of psychometric tests to better understand the quality of the YRBS questionnaire and the data collected with it.
Methodology studies conducted by CDC in 1992, 2000, and 2002 to measure the reliability and validity of student responses demonstrate that most questions have substantial reliability. In addition, CDC periodically assesses the YRBS questionnaire among adolescents in cognitive laboratory and focus group settings to better understand how adolescents answer specific questions.
• The survey environment. CDC carefully designed its survey administration procedures to protect the confidentiality of schools and the anonymity of students.
Through formal CDC workshops, state and local YRBS coordinators learn and practice such procedures as making sure students know the survey is voluntary; sitting students as far apart as possible throughout the classroom; and assuring that neither survey administrators nor classroom teachers wander around the classroom while students are taking the survey.
They tell students about the importance of providing honest answers; give students the option to seal their completed questionnaire in blank envelopes so no one can see their responses; and provide for make-ups for absent students only when their privacy can be protected.
• The questionnaire. From the beginning, CDC designed the YRBS questionnaire to protect the anonymity of students. No names or other types of personally identifying information are ever collected on the questionnaire or answer sheet.
The questionnaire is designed so that students who engaged in few risky behaviors and those who engaged in many take the same amount of time to complete it.
In addition, the YRBS questionnaire has about a seventh-grade reading level. This helps students accurately comprehend questions and response options.
• Edit and logic checks. Regardless of which state, school district, or territory conducts the YRBS, CDC processes all YRBS data. When completed questionnaires are sent to CDC, the data are edited for inconsistent responses.
More than 100 edit checks are conducted on each YRBS questionnaire to remove inconsistent responses. For example, students who report carrying a weapon on school property also must have reported carrying a weapon anywhere, or the responses to these two questions are deleted.
CDC also believes adolescents tell the truth when completing the YRBS because YRBS data are consistent over time, and they match health outcome data.
Since 1991, while the prevalence of some behaviors has increased or decreased significantly over time, most changes have been gradual and in one direction -- either up or down -- and have not bounced around from year to year.
Subgroup differences are logical and have remained constant over time. For example, many behaviors like drug use and sexual experience consistently increase by grade, while others like physical fighting consistently decrease by grade. Other behaviors vary consistently by gender. Males are always far more likely than females to use smokeless tobacco.
YRBS trends are consistent with health outcome trends.
For example, YRBS data from the past decade indicate that the prevalence of sexual experience is decreasing and the prevalence of condom use among sexually active students is increasing. During this same period, rates of teen pregnancies, teen births, and sexually transmitted disease among adolescents also have decreased.
CDC also regularly discusses YRBS procedures and data with local and state education and health agencies and receives feedback on all aspects of its surveillance system.
This feedback is used to pursue methodological and questionnaire changes that will further encourage students to tell the truth and improve the quality of the YRBS data for all users.
Howell Wechsler is the director of the Division of Adolescent and School Health at the Centers for Disease Control and Prevention.