With sentiment analysis, we are concerned with who holds what type of feeling about a specific product or topic. This can tell us that citizens of a particular city hold positive or negative feelings about the performance of a sports team. They may hold a different sentiment about the team's performance versus its management.

It can be useful to automatically determine the sentiment for aspects, or attributes, of a product and then display the results in some meaningful manner. This is illustrated using a review of the 2014 Camry from Kelly Blue Book (http://www.kbb.com/toyota/camry/2014-toyota-camry/?r=471659652516861060), as shown in the following figure.

The attributes, such as Overall Rating and Value, are depicted both as a bar graph and as a numeric value. The calculation of these values can be performed automatically using sentiment analysis.

Sentiment analysis can be applied to a sentence, a clause, or an entire document. Sentiment analysis may be either...