Randomization and Enrollment
To maintain reasonably good balance among the four
treatment groups, participants were randomized using a
stratified block randomization procedure. Factors utilized
in this procedure were treatment site, age, and
gender.
Subjects were enrolled using a multiple gating procedure
in which parents/guardians of prospective participants
first completed an initial telephone screen (Gate
A). Following the phone screen, those families who met
basic eligibility criteria were then invited to the site’s
clinic. At the clinic, informed consent and assent were