Construction of a sentimental word dictionary

The Web has plenty of reviews, comments and reports about products, services, government policies, institutions, etc. The opinions expressed in these reviews influence how people regard these entities. For example, a product with consistently good reviews is likely to sell well, while a product with numerous bad reviews is likely to sell poorly. Our aim is to build a sentimental word dictionary, which is larger than existing sentimental word dictionaries and has high accuracy. We introduce rules for deduction, which take words with known polarities as input and produce synsets (a set of synonyms with a definition) with polarities. The synsets with deduced polarities can then be used to further deduce the polarities of other words. Experimental results show that for a given sentimental word dictionary with D words, approximately an additional 50% of D words with polarities can be deduced. An experiment is conducted to find the accuracy of a random sample of the deduced words. It is found that the accuracy is about the same as that of comparing the judgment of one human with that of another.