Is this really proof. These nurses knew that they were the subject of a study, they knew that the hours were temporary, and they knew that if the outcome was p

Is this really proof. These nurses knew that they were the subject of a study, they knew that the hours were temporary, and they knew that if the outcome was positive they may get to work less and get paid the same for the rest of their lives. Of course they had a very strong incentive to organize more activities and be as good as possible for the trial period. If you really want a study, try finding workers in a factory who work 6 hours and then compare their productivity to workers in a different factor who work 8 hours.