The application of machine learning methods to the dialogue management component of spoken dialogue systems is a growing research area. Whereas traditional methods use handcrafted rules to specify a dialogue policy, machine learning techniques seek to learn dialogue behaviours from a corpus of training data. In this paper, we identify the properties of a corpus suitable for training machine-learning techniques, and propose a framework for collecting dialogue data. The approach is akin to a “Wizard of Oz” set-up with a “wizard” and a “user”, but introduces several novel variations to simulate the ASR communication-channel. Speciﬁcally, a turn-taking model common in spoken dialogue system is used, and rather than hearing the user directly, the wizard sees simulated speech recognition results on a screen. The simulated recognition results are produced with an error-generation algorithm which allows the target WER to be adjusted. An evaluation of the algorithm is presented.