Evaluating smoking prevention and cessation programs requires valid data collection. This study examined two survey modes--face-to-face (FTF) interview and self-administered questionnaire (SAQ)--comparing response rates, sample characteristics, data quality, and response effects. From two family planning clinics, 601 female Latina and African American clients ages 12 to 21 were recruited and randomized to either group. Results reveal that neither mode is superior to the other. The SAQ may therefore be preferable for this population, despite its higher rate of incompletes, because it yields results similar to the FTF yet is more cost effective and less disruptive to clinic routines.