title: Extracting PICO Sentences from Clinical Trial Reports usingSupervised Distant Supervision.
abstract: Systematic reviewsunderpin Evidence Based Medicine (EBM) by addressing precise clinical questions via comprehensive synthesis of all relevant published evidence. Authors of systematic reviews typically define a Population/Problem, Intervention, Comparator, and Outcome (aPICOcriteria) of interest, and then retrieve, appraise and synthesize results from all reports of clinical trials that meet these criteria. Identifying PICO elements in the full-texts of trial reports is thus a critical yet time-consuming step in the systematic review process. We seek to expedite evidence synthesis by developing machine learning models to automatically extract sentences from articles relevant to PICO elements. Collecting a large corpus of training data for this task would be prohibitively expensive. Therefore, we derivedistant supervision(DS) with which to train models using previously conducted reviews. DS entails heuristically deriving 'soft' labels from an available structured resource. However, we have access only to unstructured, free-text summaries of PICO elements for corresponding articles; we must derive from these the desired sentence-level annotations. To this end, we propose a novel method -supervised distant supervision(SDS) - that uses a small amount of direct supervision to better exploit a large corpus of distantly labeled instances bylearningto pseudo-annotate articles using the available DS. We show that this approach tends to outperform existing methods with respect to automated PICO extraction.
authors.affiliation: School of Information and Department of Computer Science, University of Texas at Austin, Austin, TX, USA.
authors.forename: Byron C
authors.initials: BC
authors.lastname: Wallace
authors.affiliation: Doctor Evidence, Santa Monica, CA, USA.
authors.forename: Joël
authors.initials: J
authors.lastname: Kuiper
authors.affiliation: Department of Chemistry, University of Texas at Austin, Austin, TX, USA.
authors.forename: Aakash
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Department of Computer Science, University of Texas at Austin, Austin, TX, USA.
authors.forename: Mingxi Brian
authors.initials: MB
authors.lastname: Zhu
authors.affiliation: Department of Primary Care & Public Health Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK.
authors.forename: Iain J
authors.initials: IJ
authors.lastname: Marshall
keywords: Evidence-based medicine; data extraction; distant supervision; natural language processing; text mining