Assigning a person to the experimental group is the same as scoring that person “yes” on the stimulus, and assigning “no” to the person in the control group.
Considerations: who participates fully; who misses participation in the program periodically; who misses participation in the program a lot?
Measures may need to be included to measure level of participation.
The problems may be more difficult than that.
The factors to consider should be addressed thoroughly.