  Anaphoric reference is an aspect of language interpretation covering a
variety of types of interpretation beyond the simple case of identity reference
to entities introduced via nominal expressions covered by the traditional
coreference task in its most recent incarnation in ONTONOTES and similar
datasets. One of these cases that go beyond simple coreference is anaphoric
reference to entities that must be added to the discourse model via
accommodation, and in particular split-antecedent references to entities
constructed out of other entities, as in split-antecedent plurals and in some
cases of discourse deixis. Although this type of anaphoric reference is now
annotated in many datasets, systems interpreting such references cannot be
evaluated using the Reference coreference scorer Pradhan et al. (2014). As part
of the work towards a new scorer for anaphoric reference able to evaluate all
aspects of anaphoric interpretation in the coverage of the Universal Anaphora
initiative, we propose in this paper a solution to the technical problem of
generalizing existing metrics for identity anaphora so that they can also be
used to score cases of split-antecedents. This is the first such proposal in
the literature on anaphora or coreference, and has been successfully used to
score both split-antecedent plural references and discourse deixis in the
recent CODI/CRAC anaphora resolution in dialogue shared tasks.
