Negation and modality triggers are identified and their scope is determined (Rosenberg et al., 2012) in order to extract the contextaware sentiment association values 4 with PMI for unigrams, bigrams, and dependency triples (typegovernor-dependent).
for a term to fall into the positive categories, it has to occur at least twice as often in positive tweets as in negative tweets, thus positive terms have association scores greater than 1.