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Single-Blind and Double-Blind Designs

This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.

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In a single-blind design the participant does not know their condition; in a double-blind design neither participant nor experimenter knows.

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In a drug trial, the nurse handing out pills and the patient swallowing them are both working from coded bottles.

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Blinding the participant alone leaves the experimenter's expectations in the data.