Teira Serrano, David2024-05-212024-05-212012-12-25https://hdl.handle.net/20.500.14468/19418In this paper, I am going to present and defend the following claims. First, if the participants are not indifferent regarding treatments, we need to implement a blinding device in every trial in order to ground the Non Interference Assumption. But we cannot take its efficacy for granted: we need to test that the blinding actually controlled for the expectations of the participants and no malign unmasking spoiled the NIA. Precisely because this test is necessary, we can only blind the participants up to a certain point: we cannot deceive them. There is evidence showing that if they suspect they are being deceived, they will deviate from the trial protocol, flawing the outcome.eninfo:eu-repo/semantics/openAccessjournal articleblinding, experimenter's effect, Hawthorne effect, non interference assumption