The Influence of Context on Dialog Act Recognition
Table 15: Accuracy (%) results obtained on the second half of the Switchboard corpus using context information extracted from the n preceding segments in the form of index-tagged n-grams.
['[EMPTY]', '# Previous Segments 0', '# Previous Segments 1', '# Previous Segments 2', '# Previous Segments 3', '# Previous Segments 4', '# Previous Segments 5']
In order to compare the results obtained using context information in the form of automatic dialog act labels with the ones obtained using n-grams, we also trained classifiers on the second half of the corpus using index-tagged n-grams. We can see that the results follow the same patterns as on the whole corpus, with only one preceding segment providing relevant information for the 42-label tag set variant, while for the other variants the second preceding segment is still able to improve accuracy. On the other hand, for the other variants, the results are around 1.50 percentage points above the ones obtained using automatic labels predicted by a classifier trained on the first half of the corpus. Furthermore, although the results are still below the ones obtained using automatic labels predicted by a classifier trained on the second half of the corpus, that difference is not statistically significant.