  We report here on a study of interannotator agreement in the coreference task
as defined by the Message Understanding Conference (MUC-6 and MUC-7). Based on
feedback from annotators, we clarified and simplified the annotation
specification. We then performed an analysis of disagreement among several
annotators, concluding that only 16% of the disagreements represented genuine
disagreement about coreference; the remainder of the cases were mostly
typographical errors or omissions, easily reconciled. Initially, we measured
interannotator agreement in the low 80s for precision and recall. To try to
improve upon this, we ran several experiments. In our final experiment, we
separated the tagging of candidate noun phrases from the linking of actual
coreferring expressions. This method shows promise - interannotator agreement
climbed to the low 90s - but it needs more extensive validation. These results
position the research community to broaden the coreference task to multiple
languages, and possibly to different kinds of coreference.

Computation and Language;Computation and Language