Exploring unlikely errors using video games: An example in number entry research

A common and important feature of many safety critical interactive devices is number entry. In hospitals, number entry takes the form of setting drug parameters such as doses, volumes, etc. There are several ways a number entry interface can be designed - with different consequences for error and speed. Nurses and healthcare practitioners usually have to interact with different interfaces often under pressure and stress of taking care of patients with different health conditions. Error rates in practice are low, undetected error rates are even lower and obtaining the context in which the errors occur is often incredibly difficult due to poor logging systems in many medical devices and high cost of planning and conducting empirical studies. Laboratory based studies also suffer similar limitations in that, without interventions, error rates are also too low to study. This paper explores the benefits of using a gaming context to study safety critical systems. We argue that a game paradigm provides a way that overcomes many of the problems of studying low error rates in safety critical systems and specifically for number entry in medical contexts

Issues in number entry user interface styles: Recommendations for mitigation

Interacting with numbers is a core part of using many interactive computer systems from the remote controls of electronic media appliances to user interfaces of high-integrity systems such as medical devices. Number entry systems are widely used on mobile devices. A wide variety of different user interface designs exist for interacting with numbers. The intricacies of the different styles are not well understood by designers and developers, especially for handling use error. This paper reviews these issues and provides recommendations for mitigating them

Using gherkin to extract tests and monitors for safer medical device interaction design

Number entry systems on medical devices are safety critical and it is important to get them right. Interaction design teams can be multidisciplinary, and in this work we present a process where the requirements of the system are drawn up using a Controlled Natural Language (CNL) that is understandable by non-technical experts or clients. These CNL requirements can also be directly used by the Quality Assurance (QA) team to test the system and monitor whether or not the system runs as it should once deployed. Since commonly, systems are too complex to test all possible execution paths before deployment, monitoring the system at runtime is useful in order to check that the system is running correctly. If at runtime, it is discovered that an anomaly is detected, the relevant personnel is notified through a report in natural language.peer-reviewe

Visualizing Magnitude: Graphical Number Representations Help Users Detect Large Number Entry Errors

Nurses frequently have to program infusion pumps to deliver a prescribed quantity of drug over time. Occasional errors are made in the performance of this routine number entry task, resulting in patients receiving the incorrect dose of a drug. While many of these number entry errors are inconsequential, others are not; infusing 100 ml of a drug instead of 10 ml can be fatal. This paper investigates whether a supplementary graphical number representation, depicting the magnitude of a number, can help people detect number entry errors. An experiment was conducted in which 48 participants had to enter numbers from a ‘prescription sheet’ to a computer interface using a keyboard. The graphical representation was supplementary and was shown both on the ‘prescription sheet’ and the device interface. Results show that while overall more errors were made when the graphical representation was visible, the graphical representation helped participants to detect larger number entry errors (i.e., those that were out by at least an order of magnitude). This work suggests that a graphical number entry system that visualizes magnitude of number can help people detect serious number entry errors

Safer User Interfaces: A Case Study in Improving Number Entry

Numbers are used in critical applications, including finance, healthcare, aviation, and of course in every aspect of computing. User interfaces for number entry in many devices (calculators, spreadsheets, infusion pumps, mobile phones, etc.) have bugs and design defects that induce unnecessary use errors that compromise their dependability. Focusing on Arabic key interfaces, which use digit keys 0-9-· usually augmented with correction keys, this paper introduces a method for formalising and managing design problems. Since number entry and devices such as calculators have been the subject of extensive user interface research since at least the 1980s, the diverse design defects uncovered imply that user evaluation methodologies are insufficient for critical applications. Likewise, formal methods are not being applied effectively. User interfaces are not trivial and more attention should be paid to their correct design and implementation. The paper includes many recommendations for designing safer number entry user interfaces

Unreliable numbers: error and harm induced by bad design can be reduced by better design

Number entry is a ubiquitous activity and is often performed in safety- and mission-critical procedures, such as healthcare, science, finance, aviation and in many other areas. We show that Monte Carlo methods can quickly and easily compare the reliability of different number entry systems. A surprising finding is that many common, widely used systems are defective, and induce unnecessary human error. We show that Monte Carlo methods enable designers to explore the implications of normal and unexpected operator behaviour, and to design systems to be more resilient to use error. We demonstrate novel designs with improved resilience, implying that the common problems identified and the errors they induce are avoidable

Developing and Verifying User Interface Requirements for Infusion Pumps: A Refinement Approach

It is common practice in the description of criteria for the acceptable safety of systems for the regulator to describe safety requirements that should be satisfied by the system. These requirements are typically described precisely but in natural language and it is often unclear how the regulator can be assured that the given requirements are satisfied. This paper is concerned with a rigorous refinement process that demonstrates that a precise requirement is satisfied by the specification of a given device. It focuses on a particular class of requirements that relate to the user interface of the device. For user interface requirements, refinement is made more complex by the fact that systems can use different interaction devices that have very different characteristics. The described refinement process recognises an input/output hierarchy

Making healthcare safer by understanding, designing and buying better IT

When nobody or nothing notices an error, it may turn into patient harm. We show that medical devices ignore many errors, and therefore do not adequately support patient safety. In addition to preventable patient harm, errors may be reported ignoring potential flaws in medical device design, and front line staff may be inappropriately blamed. We present some suggestions to improve reporting and the procurement of hospital equipment