Medical Records   Received Full Series Did Not Complete Series Correct Recallb (%) P Value Gender-Specific Reporting       < 0.171c Female Self-Report (n = 136)     55.1   Received Full Series 36 5     Did Not Complete Series 8 39     Unsure 31 17     Male Self-Report (n = 81)     58    Received Full Series 6 1     Did Not Complete Series 1 41     Unsure 5 27     Age-Specific Reporting       < 0.043d 12-14 (n = 29)     44.8   Received Full Series 3 1     Did Not Complete Series 1 10     Unsure 4 10     15-17 (n = 92)     55.4    Received Full Series 16 0      Did Not Complete Series 4 35     Unsure 20 17     18-19 (n = 56)     50   Received Full Series 10 5     Did Not Complete Series 3 18      Unsure 8 12     20-23 (n = 40)     75   Received Full Series 13 0     Did Not Complete Series 1 17     Unsure 4 5     All Participants Self Report (n = 217)     56.2   Received Vaccine 42 6     Did Not Complete Series 9 80      Unsure 36 44

Table 3: Completion of HPV Vaccination Series: Agreement of Gender- and Age-Specific Self-Report to Medical Records (n=217). Note: Completion = 3 doses; Of all participants self-report: sensitivity 48.3 (i.e. 42/ (42+9+36)), specificity 61.5 (i.e. 80/(80+6+44)), positive predictive value 45.7 (i.e. 42/(42+6+44)), negative predictive value 64.0 (i.e. 80/(80+9+36)). Correct Recall=proportion of participants who accurately identify vaccination status (including completing series, or not completing series) based on medical records; those who are "unsure" or "unsure but at least one" are incorrect. OR Female (vs. Male): 0.889, 95% CI 0.51-1.55. OR 20-23 (vs<20): 2.77, 95% CI 1.28-6.