Fig. 3

Schematic of a typical data extraction process. The above illustration concerns the example task of extracting the study sample size. In general, these tasks involve labelling individual words. The word (or ‘token’) at position t is represented by a vector. This representation may encode which word is at this position and likely also communicates additional features, e.g. whether the word is capitalized or if the word is (inferred to be) a noun. Models for these kinds of tasks attempt to assign labels all T words in a document and for some tasks will attempt to maximize the joint likelihood of these labels to capitalize on correlations between adjacent labels