When we compare both datasets we find that the ACE data is made up of newswire articles, Broadcast news, broadcast conversational texts, weblogs, usenet newsgroup texts and conversational telephone speech that has been transcribed, whereas the IBC corpus consists mainly of newswire articles reporting fatalities during the Iraqi War.
event instances in the ACE data describing the "Die" event type are likely to report fatalities not only from Iraq but also from more diverse contexts and situations.