VUACLTL at SemEval 2016 Task 12: A CRF Pipeline to Clinical TempEval

This paper describes VUACLTL, the system the CLTL Lab submitted to the SemEval 2016 Task Clinical TempEval. The system is based on a purely data-driven approach based on a cascade of seven CRF classifiers which use generic features and little domain knowledge. The challenge consisted in six subtasks related to temporal processing clinical notes from raw text (event and temporal expression detection and attribute classification, temporal relation classification between events and the Document Creation Time, and narrative container detection). The system was initially developed to process newswire texts and then re-trained to process clinical notes. This had an impact on the results, which are not equally competitive for all the subtasks.