The Wizard of Oz method is a process that allows a user to interact with an interface without knowing that the responses are being generated by a human rather than a computer by having someone behind-the-scenes who is pulling the levers and flipping the switches. This process allows researchers to test a concept by having one practitioner – the ‘Moderator’ – leading the session face to face with each user, whilst another practitioner – the ‘Wizard’ – controls the responses sent to the user via the chosen device. Wizard of Oz: This is a comparatively uncommon technique but has seen some use in mobile devices. It has the advantage of producing a highly changeable set of reactions, but can be quite costly and difficult to undertake. The Wizard of Oz methodology allows you to test users’ reactions to a system before you even have to think about development.