Information Extraction from Single and Multiple Sentences

Some Information Extraction (IE) systems are limited to extracting events expressed in a single sentence. It is not clear what effect this has on the difficulty of the extraction task. This paper addresses the problem by comparing a corpus which has been annotated using two separate schemes: one which lists all events described in the text and another listing only those expressed within a single sentence. It was found that only 40.6% of the events in the first annotation scheme were fully contained in the second.