Sarah Wiseman

Designing Devices With the Task in Mind Which Numbers Are Really Used in Hospitals

Objective: We studied the patterns of digits and numbers used when programming infusion pumps with the aim of informing the design of number entry interfaces. Background: Number entry systems on medical devices are designed with little thought given to the numbers that will be entered. In other fields, text and number entry interfaces are designed specifically for the task that they will be used for. Doing so allows for faster and more accurate interaction. Method: In Study 1, logs were taken from infusion pumps used in a hospital. Information about the numbers being typed was extracted. For Study 2, three common number entry interfaces were evaluated in light of these results to determine which were best suited to the task of programming infusions. Results: There are clear patterns in the numbers being used in hospitals. The digit 0 is used far more frequently than any other digit. The numbers 1,000, 100, and 50 are used in nearly half of all infusions. Study 2 demonstrates that interfaces are not optimized for entering such data. Conclusion: Changes could be made to the design of the number entry interface on infusion pumps, leading to a reduction in the number of key presses necessary to program a device. We offer a set of four heuristics to guide the design of number entry interfaces on infusion devices. Application: Improving the design of the number entry interface of medical devices, such as infusion pumps, would lead to improved efficiency and a reduction in the likelihood of errors.

Using Checksums to Detect Number Entry Error

Number entry is a common task in many domains. In safety-critical environments such as air traffic control or on hospital wards, incorrect number entry can have serious harmful consequences. Research has investigated how interface designs can help prevent users from making number entry errors. In this paper, we present an experimental evaluation of two possible interface designs aimed at helping users detect number entry errors using the idea of a checksum: an additional (redundant) number that is related to the to-be-entered numbers in such a way that it is sufficient to verify the correctness of the checksum, as opposed to checking each of the entered numbers. The first interface requires users to check their own work with the help of the checksum; the second requires the user to enter the checksum along with the other numbers so that the system can do the checking. In each case, two numbers needed to be entered, while the third number served as a checksum. With the first interface, users caught only 36% of their errors. The second interface resulted in all errors being caught, but the need to enter the checksum increased entry time by 46%. When participants were allowed to choose between the two interfaces, they chose the second interface in only 12% of the cases. Although these results cannot be generalized to other specific contexts, the results illustrate the strengths and weaknesses of each way of using checksums to catch number entry errors. Hence our study can serve as a starting point for efforts to improve each method.

Tailoring number entry interfaces to the task of programming medical infusion pumps

Medical devices are often used to administer medication to patients. This task usually requires a caregiver to enter specific numerical values into a device. In such safety-critical domains, it is vital that this task can be done quickly and accurately. We consider whether tailoring the interface to make it easier for commonly entered numbers to be inputted makes this task faster and less error-prone. To evaluate this idea we take data from infusion pumps programmed on the ward and make adaptations to three existing interfaces to make the task easier (by adding buttons or altering the effects of interaction). The results of a lab-based experiment show that tailoring the interface in this way can significantly reduce the number of key presses that are required to complete the task. We also present findings regarding the process of tailoring interfaces for more general device design.

Employing Number-Based Graphical Representations to Enhance the Effects of Visual Check on Entry Error Detection

Number entry is a mundane and error-prone task. To find errors, users often rely on visual checks to compare the differences between their instructions and the numbers they have actually input, a task that is difficult for users to do accurately. We therefore propose the use of number-based graphical representations (GRs) as a complement to conventional numeric representations (NR) to enhance visual checks, so users can examine both GRs and NRs to detect errors. We conducted two experiments to explore the issues raised. Experiment 1 examined the effects of GRs and NRs on representation difference detection (i.e. checking if two GRs or NRs are identical). The two representations had a comparative performance by time and error rate. In Experiment 2, we investigated the performance of GRs and NRs with number entry tasks. While extending the task time (increased by 38%), number entry with GRs resulted in significantly fewer errors than without GRs (decreased by 60%). Participants also had a high preference for number entry with GRs. Therefore, the proposed technique is promising for number entry error reduction, and that in safety critical applications improved safety can be achieved.

Designing for the task: what numbers are really used in hospitals?

In the English language, the letters of the alphabet do not occur with equal frequency. Some letters occur far more often than others, for example the letter e occurs more frequently than z. In this paper we show that as with letters, digits too suffer from unequal distributions in some situations. Here we show that the most common digits being used when programming infusion pumps to administer drugs to patients are 0, 1, 2 and 5. The digit 9 is also frequently used to set an infusion to run at the maximum rate possible. With this information, we evaluate three current forms of infusion pump input with regards to the digits that are actually being programmed into the machines. We argue that the current number interface designs used in medical devices should take into account these findings in order to produce interfaces that are both more suitable for the task, and less error prone in use.

Control and Being Controlled: Exploring the use of Technology in an Immersive Theatre Performance

Immersive theatre is a growing trend within theatre entertainment: audience members can now wander around performances and choose how the story unfolds in front of them. Technology can be used to create novel, multi-modal experiences for audiences in these performances; but when the rules of such an experience are ill-defined, how do users react to this technology? We present an evaluation of 25 performances of an immersive, in the dark performance. Issues of control can arise in situations where technology becomes an important part of such a performance. Participants take and relinquish control in three key areas: navigation, exploration and attention during the performance, and this affects their perception of both technology and the piece itself. We discuss how technology can play a positive role in immersive theatre and other cultural settings, yet its use must be carefully choreographed to ensure the audience experience matches the intended goal.

MOODs: building massive open online diaries for researchers, teachers and contributors

Internet-based research conducted in partnership with paid crowdworkers and volunteer citizen scientists is an increasingly common method for collecting data from large, diverse populations. We wanted to leverage web-based citizen science to gain insights into phenomena that are part of peoples everyday lives. To do this, we developed the concept of a Massive Open Online Diary (MOOD). A MOOD is a tool for capturing, storing and presenting short updates from multiple contributors on a particular topic. These updates are aggregated into public corpora that can be viewed, analysed and shared. MOODs offer a novel method for crowdsourcing diary-like data in a way that provides value for researchers, teachers and contributors. MOODs also come with unique community-building and ethical challenges. We describe the benefits and challenges of MOODs in relation to Errordiary.org, a MOOD we created to aid our exploration of human error.

Use Your Words: Designing One-time Pairing Codes to Improve User Experience

The Internet of Things is connecting an ever-increasing number of devices. These devices often require access to personal information, but their meagre user interfaces usually do not permit traditional modes of authentication. On such devices, one-time pairing codes are often used instead. This pairing process can involve transcribing randomly generated alphanumeric codes, which can be frustrating, slow and error-prone. In this paper, we present an improved pairing method that uses sets of English words instead of random strings. The word method, although longer in terms of character length, allows users to pair devices more quickly, whilst still maintaining the complexity necessary for secure interactions.

The Effect Of Interface Type On Visual Error Checking Behavior

During data entry tasks, small errors can result in catastrophe, for instance adding an extra zero to a drug dose when programming an infusion in a hospital. For this reason understanding users’ error checking behavior is highly important. One aspect that can affect error checking is the interface that a user must interact with to enter data. Often user interaction with interfaces is evaluated based on speed or error rate. In this paper, in addition to this, we also explore how different types of interface can affect a user’s error checking behavior in a multitasking environment. We show that a fast to use and familiar interface discourages users from carrying out thorough visual checking in a number transcription task. We also found that having participants perform an additional secondary task while doing the number entry task made participants less likely to check the inputted numbers for errors.

Short links and tiny keyboards

Link-shortening services save space and make the manual entry of URLs less onerous. Short links are often included on printed materials so that people using mobile devices can quickly enter URLs. Although mobile transcription is a common use-case, link-shortening services generate output that is poorly suited to entry on mobile devices: links often contain numbers and capital letters that require time consuming mode switches on touch screen keyboards. With the aid of computational modeling, we identified problems with the output of a link-shortening service, bit.ly. Based on the results of this modeling, we hypothesized that longer links that are optimized for input on mobile keyboards would improve link entry speeds compared to shorter links that required keyboard mode switches. We conducted a human performance study that confirmed this hypothesis. Finally, we applied our method to a selection of different non-word mobile data-entry tasks. This work illustrates the need for service design to fit the constraints of the devices people use to consume services. A systematic critique of identifier schemas used by existing link-shortening services.A set of computational models that identify potentially superior schema designs.An empirical user study that confirms the superiority of our new schema designs.