%0 Journal Article %T Frustratingly Easy Domain Adaptation %A Hal Daum¨¦ III %J Computer Science %D 2009 %I arXiv %X We describe an approach to domain adaptation that is appropriate exactly in the case when one has enough ``target'' data to do slightly better than just using only ``source'' data. Our approach is incredibly simple, easy to implement as a preprocessing step (10 lines of Perl!) and outperforms state-of-the-art approaches on a range of datasets. Moreover, it is trivially extended to a multi-domain adaptation problem, where one has data from a variety of different domains. %U http://arxiv.org/abs/0907.1815v1