We conducted several sensitivity analyses to investigate how the model’s results were dependent on the estimates chosen for the probabilities and costs. First, we conducted univariate sensitivity analyses where the estimates of key variables were varied to reflect the plausible range reported in the literature. The percentage of decrease in girls using reproductive health care services because of loss of confidentiality is varied between 47%9 and 27% (Carol A. Ford, MD, written communication, April 1, 2004; Abigail English, JD, written communication, April 15, 2004). We also considered the very conservative case where the percentage of girls who stop using reproductive health care in response to reporting requirements is arbitrarily adjusted downward to only 10%, well below published estimates. We considered a lower cost for a visit, $14.13, from a published study looking at visit costs in a Texas publicly funded clinic.27 We used the lower rate of positive findings for chlamydia infection, 6.7%, in adolescents presenting for routine checkups in a large California health maintenance organization.30 We varied the cost of screening from $9.10 (the cost of the cervical swab test) to $16.00 (the upper limit for the cost of the nucleic acid amplification urine-based test) (Bonnie K. Smith, written communication, June 4, 2003; Carlos Roca, written communication, June 4, 2003; Onesia Bishop, PhD, written communication, June 12, 2003). The upper limits for the costs of treating chlamydia infection and gonorrhea were represented by the following Medicaid reimbursements to a private pharmacy: $31.67 for azithromycin, $6.46 for doxycycline hyclate, and $10.07 for ciprofloxacin.44,45 We varied the costs of treating chlamydia infection from $2.31 (cost to TDH of doxycycline) to $31.67 (Medicaid cost of azithromycin) and the cost of treating gonorrhea to $10.07 (Medicaid cost of ciprofloxacin). We considered the following ranges of probability of progression to PID: 20% to 40% for chlamydia infection and 10% to 40% for gonorrhea.31- 35 The low and high lifetime medical cost estimates for PID were $135739,42 and $3965,34 respectively. We used plus and minus 10% of base-case values to vary the effectiveness of family planning in averting pregnancies, births, and abortions as well as the costs of births and abortions. Next, we conducted a multivariate sensitivity analysis by varying all variables simultaneously and considered a best-case scenario and a worst-case scenario. In the best-case scenario, all estimates and probabilities were set at their best levels (low for costs and high for savings), and in the worst-case scenario, all estimates and probabilities were set at their worst levels (high for costs and low for savings).