Sentiment profiles of multiword expressions in test-taker essays: The case of noun-noun compounds

The property of idiomaticity vs. compositionality of a multiword expression traditionally pertains to the semantic interpretation of the expression. In this article, we consider this property as it applies to the expression's sentiment profile (relative degree of positivity, negativity, and neutrality). Thus, while heart attack is idiomatic in terms of semantic interpretation, the sentiment profile of the expression (strongly negative) can, in fact, be determined from the strongly negative profile of the head word. In this article, we (1) propose a way to measure compositionality of a multiword expression's sentiment profile, and perform the measurement on noun-noun compounds; (2) evaluate the utility of using sentiment profiles of noun-noun compounds in a sentence-level sentiment classification task. We find that the sentiment profiles of noun-noun compounds in test-taker essays tend to be highly compositional and that their incorporation improves the performance of a sentiment classification system.