Sample frame
The sampling frame was derived from public and private school enrollment records in Lucas County, Ohio. School attendance, however, was not a requirement for inclusion. A stratified, random sample (n=1,316) was then drawn from all 7th, 9th, and 11th grade youth residing in Lucas County in the fall of 2000.

Adolescent quantitative interviews
Structured, in-home interviews were conducted utilizing laptop computers pre-loaded with the questionnaire. An interviewer administered both the beginning and end of the questionnaire, while the adolescent was given control of the computer to complete the sensitive questions. This afforded the adolescent respondents the assurance of privacy and confidentiality. This structured in-home interview format is being utilized across the waves.

Adolescent qualitative interviews
In-depth interviews were conducted at the first and third waves with a sub-sample (n=100) of the respondents. The purpose of these interviews was to first establish an overview of the adolescents' experiences with friends, dating, and romantic relationships. The differences between friends and boy/girlfriends and the nature of the adolescents' current or most recent romantic relationship was also reviewed. Additional in-depth interviews are scheduled for the fourth wave.

Parent interviews
A parent or guardian also completed a short, self-administered questionnaire at the first wave. This allowed us to establish a household roster and document any major disruptions or changes in the household. Parents were also asked about their past and present behaviors, educational level, work experience, and parenting methods.