Commonly Asked Questions about Random Assignment

This brief reviews eight common questions about random assignment, a type of study that allocates participants by chance into either a treatment group or an experimental group.

1. Why do random assignment?
2. Why won’t a comparison site work just as well?
3. Why won’t an overflow model work just as well?
4. Why can’t we just track changes in outcomes over time in the same site?
5. What happens to cases assigned to the control group? Aren’t they being denied services?
6. Isn’t this illegal or unethical?
7. Isn’t random assignment unfair?
8. Will families be angry if they learn that some families are getting a service and they are not?

The brief then reviews key steps for implementing random assignment, from establishing a work plan agreement with sites to obtaining informed consent.