The dialogues vary in length are five exchanges or less with consisting of only two exchanges of all the dialogues As mentioned above  dialogues in whi HMIHY successfully automates the customer s call as illustrated in Figure   are referred to as TASKSUCCESS  Other calls  which are problematic are divided into three categories  The first category  referred to as HANGUP
results from a customer s decision to hang up on the system A sample HANGUP dialogue is in Figure A caller may hang up because s he is frustrated with the system  our goal is to learn from the corpus which system behaviors led to the caller s frustration

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The second problematic category WIZARD results from a human customer care agent s decision to take over the call from the system Because HMHY is experimental each call during the field trial was monitored by a human agent serving as a wizard who could override the system There were a number of agents who participated as wizards during the trial of HMHY and each wizard was simply told to take over the call if s  he perceived problems with the system s performance  The wizard s decision was logged by the experimental setup resulting in labelling the call as one that the wizard took over  Of course we can only infer what might have motivated the wizard to take over the call  but we assume that the wizard had good reason for doing so A dialogue where the wizard decided that the dialogue was problematic and took over the call is shown in Figure

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The third problematic category the TASKFAILURE dialogues  are cases where the sys tem completed the call but carried out a task that was not the one that the customer