Using Task Models to Understand the Intersection of Numeracy Skills and Technical Competence With Medical Device Design

Task models are used in many different ways throughout the design and development of interactive systems. When the interactive systems are safety critical, task models can play an important role in ensuring system behaviours are consistent with user requirements, which may help to prevent errors. While task models can be used to describe a user’s goals and the steps required to achieve that goal, to understand where user errors may occur we also need to consider the users’ understanding of how to perform a task and how this relates to the system they are using. Our focus is on the use of medical devices such as syringe drivers and infusion pumps for intravenous medication, which forms a major part of hospital inpatient care throughout the world. While we might rely on software engineering and human factors techniques to ensure correctness of such devices, their use by medical personnel in practice includes other factors that are equally important. These include training medical personnel in the use of medical devices. Also numeracy education for medical staff to ensure that they are able to set up and perform the necessary calculations to convert prescribed medication into the appropriate values and measures for their delivery mechanisms. We have developed an approach that aims to bring together concepts of technology design (both functional correctness and usability concerns), numeracy and medication delivery competency. In order to do so we use task models as a common language that enables us to consider these different domains in a single way. We find that the ability to describe the two domains within a single process allows us to compare models of knowledge, tasks and use of devices, which can elicit potential mismatches and problems.