“…[29][30][31][32] However, poor implementation of schoolbased programs at scale, including problems of curricula lacking basic information on condoms and contraception, poor teaching, and short program durations, have often resulted in a lack of fidelity to the designed intervention, reducing program effectiveness. 33 Our study supports the idea that text-messaging programs may be effective ways to fill this gap, by providing accurate and complete information via a medium with which adolescents are comfortable. Moreover, text-messaging programs can be tailored to the audience both in terms of cultural and individual characteristics 34 , and they can inexpensively reach a large and diverse population-the marginal costs of the interactive and unidirectional programs per participant were US$1.91 and US$0.30, respectively.…”