Once permission was obtained from the necessary parties in each school, a passive consent procedure was developed. Letters were sent through the school to parents informing them about the study and outlining the procedure by which they could deny permission for their child to participate in the survey if they wished their child to be excluded. In most cases, parents were instructed to call the main office of their child’s high school to deny permission for their child’s participation. From these phone calls, a list of students who were not eligible to participate was compiled for use on the survey administration day. If no message was received from a parent, parental permission was assumed. The passive consent procedure was approved by all participating schools and by the Institutional Review Board of the Yale University School of Medicine.
