Sentiment analysis refers to the automatic extraction
of sentiments from a natural language text. We study the
effect of subjectivity-based features on sentiment classification
on two lexicons and also propose new subjectivity-based features
for sentiment classification. The subjectivity-based features we
experiment with are based on the average word polarity and the
new features that we propose are based on the occurrence of
subjective words in review texts. Experimental results on hotel
and movie reviews show an overall accuracy of about 84% and
71% in hotel and movie review domains respectively; improving
the baseline using just the average word polarities by about 2%
points.