  TechStep is a randomized trial of a mobile health interventions targeted
towards transgender adolescents. The interventions include a short message
system, a mobile-optimized web application, and electronic counseling. The
primary outcomes are self-reported sexual risk behaviors and uptake of HIV
preventing medication. In order that we may evaluate the efficacy of several
different combinations of interventions, the trial has a sequentially
randomized design. We use a causal framework to formalize the estimands of the
primary and key secondary analyses of the TechStep trial data. Targeted minimum
loss-based estimators of these quantities are described and studied in
simulation.
