From Table 2 , we can see that the BERT base model achieved almost 12% points improvement over the Bi-LSTM baseline and 15% points over<cite> Bai and Zhao (2018)</cite> . When fine-tuned on in-domain data in the crossvalidation setting, the improvement increases to around 17% points. Cross-Domain In-Domain Bi-LSTM + w2v 300 32.97 46.49<cite> Bai and Zhao (2018)</cite> 29.52 55.90