Predicting Causes of Reformulation in Intelligent Assistants
Table 5: Distribution of input type switches (%). For example, V2T means input type of U1 is voice input and that of U2 is text input.
['[EMPTY]', '[BOLD] V2V', '[BOLD] T2T', '[BOLD] V2T', '[BOLD] T2V']
Here, we analyze the correlation between error causes and input types. Input types sometimes differ between U1 and U2. For example, \newciteJiang13 have reported that users switch from voice inputs to text inputs when they encounter ASR errors. As \newciteJiang13 have shown, voice-to-text switches are more frequent for ASR error than in other causes. We can also see that both text-to-voice and voice-to-text switches are observed for NLU error. Compared with these causes, input type switches are rarely observed for No error. Interestingly, text-to-voice switches are not observed for No error either. On the other hand, small number of voice-to-text switches are observed for No error. We guess that some users switch input from voice to text when they submit similar query by copy and paste the part of ASR result of their previous utterances. These findings suggest that users tend to keep using the same input type while their intents are correctly recognized. Unlike the other causes, no input type switches are observed for LG error. We expect this is due to insufficient data.