A randomized controlled trial may test effectiveness of exercise.
A randomized controlled trial may test effectiveness of a (youth program).
Some high schools may participate in a randomized controlled trial.
A randomized controlled trial may test effectiveness of a (youth intervention).
A randomized trial of strengths may be conducted among attenders.
Randomized trials can be constituted-of-or-filled-with (suicide interventions).
A randomized trial can be constituted-of-or-filled-with treatments.