CRAC18 Shared Task @NAACL HLT

Event Notification Type: 
Call for Participation
Friday, 1 June 2018 to Wednesday, 6 June 2018
New Orleans
Yulia Grishina
Massimo Poesio
Submission Deadline: 
Thursday, 1 February 2018

CRAC18: Shared Task


Progress in anaphora resolution / coreference, as in other areas of NLP, is achieved not only by creating larger corpora and by developing better computational models for the task, but also by extending the range of issues considered. The creation of the coreference portion of the OntoNotes corpus (Pradhan et al, 2007) greatly boosted research in this area not only by making available a much larger resource, but also by adopting a linguistically more informed view of the task, and by extending the range of anaphoric phenomena considered (Pradhan et al, 2011; Pradhan et al, 2012).

The CRAC 2018 shared task will exploit the availability of new resources, and specifically, the second release of the ARRAU corpus (Uryupina et al, to appear), that enables the study of aspects of anaphora not considered previously, and in particular the phenomena of bridging references (Clark, 1975) and discourse deixis (a type of anaphoric reference to abstract objects) (Webber, 1991), and covering spoken dialogue as well as text. An example of bridging reference is the handles in (1), which refers to a part of the egg vases introduced in u1. (This example is from the GNOME corpus.) An example of discourse deixis is This in (2), from (Webber, 1991).

1. (u1) These “egg vases” are of exceptional quality.
(u2) basketwork bases support egg-shaped bodies
(u3) and bundles of straw form the handles.
2. For example, binocular stereo fusion is known to take place in a specific area of the cortex near the back of the head.
Patients with damage to this area of the cortex have visual handicaps but they show no obvious impairment in their ability to think.
This suggests that stereo fusion is not necessary for thought.


The proposed shared task will be articulated around a number of sub-tasks, all using the ARRAU corpus, and including the following:

- Task 1: Resolution of anaphoric identity
This sub-task will be concerned with anaphoric identity only, but covering all sub-domains of ARRAU: the RST domain (1/3 of the Penn Treebank), the TRAINS-93 domain (task-oriented dialogue), and the Pear Stories domain (spoken narrative).

- Task 2: Resolution of bridging references in text
This subtask will be focused on bridging references, using the RST domain of ARRAU.

- Task 3: Resolution of discourse deixis
This subtask will focus on discourse deixis only, using the RST domain of ARRAU.


The ARRAU corpus is distributed by LDC, that will make it available to the participants to this shared task. Participants should register for the shared task by email to Yulia Grishina ( and Massimo Poesio ( After registering, participants should download the Agreement form from the shared task website, sign it, and send it to LDC, which will then release the data.


12.12 Shared task description circulated and training data available
15.1 Test data distributed
1.2 System runs submitted
15.2 Results published
28.2 System description papers deadline
15.3 Task description paper deadline
20.3 Reviews for all papers
16.4 Camera ready versions for all papers


Yulia Grishina, University of Potsdam (chair)
Varada Kolhatkar, Simon Fraser University
Anna Nedoluzhko, Charles University in Prague
Massimo Poesio, Queen Mary University of London
Adam Roussel, University of the Ruhr at Bochum
Fabian Simonjetz, University of the Ruhr at Bochum
Olga Uryupina, University of Trento
Heike Zinsmeister, University of Hamburg