NTCIR-6 at Maryland: Chinese Opinion Analysis Pilot Task

For the Chinese opinion analysis pilot task at NTCIR-6, we tested two techniques for each of the four subtasks—identifying opinionated sentences, making polarity decisions, identifying opinion holders, and retrieving topically relevant sentences. Our opinion detection technique is based on sentiment lexicons. We explored three main issues: the effect of the size of sentiment lexicons on the accuracy of opinionated sentence identification and of polarity decisions, the effect of a simple approximation to anaphora resolution on the accuracy of opinion holder identification, and the effect of sentence expansion on the effectiveness of relevant sentence retrieval.