Wizard of Oz testing simulates a functioning product by having a human operator manually produce the responses that a real system would generate automatically. The participant interacts with what appears to be a working product while, behind the scenes, a team member plays the role of the 'wizard,' providing real-time responses. The technique, named after the scene in which the wizard is revealed to be a man operating a machine behind a curtain, allows teams to test the value and usability of a concept before building any real technology.