One team participated in the GRO task , and their results were compared with those of a preliminary system prepared by the task organizers . An analysis of the evaluation results leads us to study issues such as the need to consider the ontology structure and the need for semantic analysis , which are not seriously dealt with by current approaches to event extraction . 6 Organization of the workshop The BioNLP Shared Task 2013 ( BioNLP-ST ) workshop was organized as part of the ACL BioNLP 2013 workshop . After submission of their system results , participants were invited to submit a paper on their systems to the workshop .