Word Polarity - Sentiment Lexicon

Sentiment Lexicon

• is a collection of words (also known as polar or opinion words) associated with their sentiment orientation

Sentiment Lexicons

• SentiWordNet
• Opinion Lexicon
• General Inquirer
• MPQA
• LIWC

Word Polarity

• how likely is each word to appear in each sentiment class (e.g. positive vs negative, 1-star to 10-stars, etc)?
• can’t use raw counts
• instead use likelihood:
  • likelihood = 𝐏(𝑤|𝑐) = 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦(𝑤,𝑐) / [ 𝛴_{𝑤ᵢ∊𝑐} 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦(𝑤ᵢ,𝑐) ]
• then make then comparable between words, using scaled likelihood:
• scaled likelihood = 𝐏(𝑤|𝑐) / 𝐏(𝑤)

Logical Negation

is logical negation (e.g. no, not) associated with negative sentiment?

Semi-Supervised Learning of Lexicons

intuition:

• start with a seed set of words (e.g. good, poor)
• find other words that have similar polarity:
  • using “and” and “but”
  • using words that occur nearby in the same document
  • using WordNet synonyms and antonyms

algorithms:

• Hatzivassiloglou and McKeown for Identifying Word Polarity
• Turney Algorithm
• Using WordNet to Learn Word Polarity