To answer RQ3, which is concerned with domain adaptation, we can see in the grayed out cells in tab:results, which correspond to the cross-domain adaption case where the BERT language model is trained on the target domain, that domain adaptation works well with $2.2\%$ absolute accuracy improvement on the laptops test set and even $3.6\%$ accuracy improvement on the restaurants test set compared to BERT-base. 
 Question: By how much does their model outperform the baseline in the cross-domain evaluation?
$2.2\%$ absolute accuracy improvement on the laptops test set $3.6\%$ accuracy improvement on the restaurants test set