Casting a Wide Net: Robust Extraction of Potentially Idiomatic Expressions
Table 11: PIE extraction performance of the combined output (union) of a string-based and a parser-based system, on the development set. CS indicates case-sensitive string matching. The best score for each metric is in bold.
['[EMPTY]', 'Precision', 'Recall', 'F1-score']
We experiment with two such combinations, by simply taking the union of the sets of extracted idioms of both systems, and filtering out duplicates. Both combinations show the expected effect: a clear gain in recall at a minimal loss in precision. Compared to the in-context-parsing-based system, the combination with exact string matching yields a gain in recall of over 6%, and the combination with inflectional string matching yields an even bigger gain of almost 8%, at precision losses of 0.6% and 0.8%, respectively. This indicates that the systems are very much complementary in the PIEs they extract. It also means that, when used in practice, combining inflectional string matching and parse-based extraction is the most reliable configuration.