You wouldn't need to blind an experiment like this, I'd think. Placebo won't prevent cancer, and nocebo won't cause it. (Besides, I don't see how you can blind

You wouldn't need to blind an experiment like this, I'd think. Placebo won't prevent cancer, and nocebo won't cause it. (Besides, I don't see how you can blind it. Not like someone's not going to know whether their phone works or not!) You could try recruiting your control cohort from the National Radio Quiet Zone. I believe it's quite thinly populated, though.