Wizard of Oz Simulation

Abstract

When the first interaction model has been designed (cf. Section 4.1) interactive speech system development may either go through a phase of Wizard of Oz (WOZ) simulations as will be described in this chapter, or go straight to implementation (Chapter 6) following the implement-test-revise approach (Figure 3.1). Today’s research on interaction model design for advanced interactive speech systems often includes the WOZ experimental prototyping method. In WOZ a human (the wizard) simulates whole or part of the interaction model of the system to be developed, carrying out spoken interactions with users who are made to believe that they are interacting with a real system. WOZ is a relatively costly development method because: (1) the wizard needs a significant amount of training and support; (2) involving experimental subjects, WOZ experiments require careful planning and preparation and take time to run; and (3) experimental results have to be transcribed and analysed, which takes time and requires skill to benefit further system development. On the other hand, by producing data on the interaction between a (fully or partially) simulated system and its users, WOZ provides the basis for early tests of the system and its feasibility, as well as of the coverage and adequacy of requirements prior to implementation. The use of WOZ has so far been justified through the comparatively higher cost of having to revise an already implemented interactive speech system whose interaction model turned out to be seriously flawed, or of having to discard a system which users will not use. As recognition and parsing techniques continue to improve and the body of standard software grows, implement-test-revise methods are likely to gain ground in the design of advanced interactive speech systems.