Identifying and classifying ambiguity for regulatory requirements

Software engineers build software systems in increasingly regulated environments, and must therefore ensure that software requirements accurately represent obligations described in laws and regulations. Prior research has shown that graduate-level software engineering students are not able to reliably determine whether software requirements meet or exceed their legal obligations and that professional software engineers are unable to accurately classify cross-references in legal texts. However, no research has determined whether software engineers are able to identify and classify important ambiguities in laws and regulations. Ambiguities in legal texts can make the difference between requirements compliance and non-compliance. Herein, we develop a ambiguity taxonomy based on software engineering, legal, and linguistic understandings of ambiguity. We examine how 17 technologists and policy analysts in a graduate-level course use this taxonomy to identify ambiguity in a legal text. We also examine the types of ambiguities they found and whether they believe those ambiguities should prevent software engineers from implementing software that complies with the legal text. Our research suggests that ambiguity is prevalent in legal texts. In 50 minutes of examination, participants in our case study identified on average 33.47 ambiguities in 104 lines of legal text using our ambiguity taxonomy as a guideline. Our analysis suggests (a) that participants used the taxonomy as intended: as a guide and (b) that the taxonomy provides adequate coverage (97.5%) of the ambiguities found in the legal text.