Promoting Safe Sex Among Adolescents in Tanzania
Last registered on January 28, 2019


Trial Information
General Information
Promoting Safe Sex Among Adolescents in Tanzania
Initial registration date
September 08, 2016
Last updated
January 28, 2019 10:42 PM EST

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Primary Investigator
Other Primary Investigator(s)
PI Affiliation
George Washington University
Additional Trial Information
In development
Start date
End date
Secondary IDs
Rates of teenage pregnancy, early marriage, HIV, and other sexually transmitted infections (STIs) remain the highest in the world in Sub-Saharan Africa, despite decades of public health interventions and research. In Tanzania, 60 percent of females have sex by the age of 18, yet less than 10 percent of adolescents aged 15-19 use any modern contraceptive method (DHS 2010). Typically, family planning and sexual and reproductive health (SRH) programs combine interventions on the supply side (e.g., access to contraceptives) and demand side (e.g., education). Because these programs bundle supply and demand side services, it is impossible to discern which type of intervention is more effective at improving SRH outcomes. Moreover, even though males often control decisions around contraceptive use and SRH behavior, these programs target only females, potentially dampening their effectiveness. We are implementing a randomized controlled trial (RCT) targeting both female and male adolescents. This RCT will allow us to causally identify the differential impacts of demand side and supply side interventions and better understand the role males play in affecting SRH outcomes.
External Link(s)
Registration Citation
Muz, Jennifer and Manisha Shah. 2019. "Promoting Safe Sex Among Adolescents in Tanzania." AEA RCT Registry. January 28.
Sponsors & Partners

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Experimental Details
We are randomizing adolescents in 150 communities across three treatment arms: (1) Demand side intervention of SRH education and incentivized goal setting, (2) Supply side intervention that will provide contraceptives to girls bi-monthly, and (3) Boys intervention that will educate boys in SRH behaviors while they play soccer
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
1.) SRH behavior and biomarkers: sexual activity; pregnancies; knowledge and use of contraception methods; HIV and STI knowledge, status, and testing; and family planning goals and strategies 2.) Other health behaviors: smoking, drinking, socializing, physical activity, and self-reported physical and mental health 3.) Economic behaviors: savings, loans, business formation, employment status, hours worked, and other income-generating activities. 4.) Behavioral economic model parameters: time discounting, risk tolerance, loss aversion, optimism, and sophistication. 5.) Social network mapping: ego-centric network measures of both same and opposite gender friends, and sexual network among peers of the opposite gender.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
The 150 ELA clubs will be randomly assigned to one of the three treatment arms: 1) Demand side, 2) Supply Side, and 3) Demand side for males. An additional 50 potential ELA club areas will be assigned to the control group.

Additionally, half of the ELA members in treatment arm 1 will be randomly assigned to receive the behavioral intervention, 1.1.) Incentivized goal-setting.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by a computer
Randomization Unit
Females: the randomization unit is the club area for intervention arms 1, 2, 3, and the control arm; individual level randomization for the behavioral intervention 1.1. within intervention arm 1.

Males: In arm 3, boys will be randomized at the individual level to receive invitations to participate in the boys SRH education/soccer club (control boys will also be selected from arm 3). An additional group of control boys will be surveyed in arms 1 and 2 in order to measure male behavior when females are treated, but males are not exposed to SRH training either directly or indirectly through peers.
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
150 ELA clubs, 50 potential ELA club areas
Sample size: planned number of observations
6000 adolescents; 4000 girls and 2000 boys
Sample size (or number of clusters) by treatment arms
50 clusters control, 50 clusters in each of the three treatment arms. For the behavioral intervention within treatment arm 1, the sample size is 1,000 girls, with 500 girls treated.

For the boys intervention in arm three, the sample is 1250 boys, with 1000 treated.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
MDEs for treatment effects among females calculated assuming 80 percent power, 5 percent significance. Based on our sample sizes, we will be able to detect a minimum of a 5.3 percentage point decrease in the probability of ever having been pregnant (sd=0.306), a 9.1 percentage point decrease in the probability of ever having had sex (sd=0.476), and an 11.2 percentage point increase in the likelihood of using a condom, conditional on having sex (sd=0.482).
IRB Name
National Institute for Medical Research (NIMR)
IRB Approval Date
IRB Approval Number
IRB Name
University of California, Los Angeles Institutional Review Board
IRB Approval Date
IRB Approval Number
Analysis Plan

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