Beyond NomBank: A Study of Implicit Argumentation for Nominal Predicates

Despite its substantial coverage, Nom- Bank does not account for all within- sentence arguments and ignores extra- sentential arguments altogether. These ar- guments, which we call implicit, are im- portant to semantic processing, and their recovery could potentially benefit many NLP applications. We present a study of implicit arguments for a select group of frequent nominal predicates. We show that implicit arguments are pervasive for these predicates, adding 65% to the coverage of NomBank. We demonstrate the feasibil- ity of recovering implicit arguments with a supervised classification model. Our re- sults and analyses provide a baseline for future work on this emerging task.