Dependable keyed data entry for interactive systems

Keyed data entry is fundamental and ubiquitous, occurring when filling data fields in web forms, entering burglar alarm pass-codes, using calculators, entering drug delivery rates in infusion pumps, making cash withdrawals from cash machines, setting destinations for GPS navigation, to name but a few of its applications. Unfortunately data entry is often implemented poorly. We introduce divergence, a loss of predictability in a user interface, and show that it is in general unavoidable in data entry, and therefore a systematic approach is called for. This paper presents one such an approach. Many inter-related ideas ``fall into place''---e.g., autocompletion, prompting, automatic color coding---through the approach. The approach contrasts with conventional systems that are generally inconsistent and unhelpful to users, particularly after errors

Reducing number entry errors: solving a widespread, serious problem

Number entry is ubiquitous: it is required in many fields including science, healthcare, education, government, mathematics and finance. People entering numbers are to be expected to make errors, but shockingly few systems make any effort to detect, block or otherwise manage errors. Worse, errors may be ignored but processed in arbitrary ways, with unintended results. A standard class of error (defined in the paper) is an ‘out by 10 error’, which is easily made by miskeying a decimal point or a zero. In safety-critical domains, such as drug delivery, out by 10 errors generally have adverse consequences. Here, we expose the extent of the problem of numeric errors in a very wide range of systems. An analysis of better error management is presented: under reasonable assumptions, we show that the probability of out by 10 errors can be halved by better user interface design. We provide a demonstration user interface to show that the approach is practical. To kill an error is as good a service as, and sometimes even better than, the establishing of a new truth or fact.(Charles Darwin 1879 [2008], p. 229

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

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

Safer Interactive Medical Device Design: Insights from the CHI+MED Project

Interactive medical devices such as infusion pumps, monitors and diagnostic devices help save lives. However, they are also safety critical in that they may fail in use and patient harm or death ensue. It is not just that the software and hardware should meet their specification. The design should help ensure users do not make mistakes. Safety factors become more important as medical devices become mobile and are used by patients as part of their everyday life rather than by trained professionals in well-defined hospital environments. Regulators are increasingly taking home-use seriously as a result of device recalls due to devices that have caused patient harm. We give insights from the research on the CHI+MED project (www.chi-med.ac.uk). It has focussed on understanding how the design of interactive medical devices can support safety. CHI+MED also developed practical tools and guidance that we review

Think! Interactive Systems Need Safety Locks

This paper uses a simple analogy. A gun is designed to shoot bullets, but it is obvious that accidentally shooting is a danger one should avoid if at all possible. Thus guns have safety locks, which aim to protect users and bystanders. Interactive computer systems sometimes accidentally do bad things too, but something like “safety locks” are not often enough implemented to help protect users or bystanders from harm. Worse, user interfaces often behave quite unpredictably with erroneous input — rather than blocking errors and requiring the user to correct them. This is a bit like guns that misbehave. Computers and computers embedded in everyday devices are not always as dangerous as guns, although there are many cases where they can be as dangerous. Medical devices may give patients undetected overdoses. In-car entertainment devices, like radios, may, through their badly-designed user interfaces, cause a driver to have an accident. A slip in a spreadsheet may be the first step towards an organisation going bankrupt. And so on. The solution should include better design, including the concept of safety locks, that block some forms of user error