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Usability and Human Factors

Usability and Human Factors. Unit 4c Human Factors and Healthcare. Mechanism: Time Description: Insufficient time to perform tasks safely, apply safe practices, or monitor patients, and may reduce their communication with physicians. Examples: Little time to double-check medications

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Usability and Human Factors

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  1. Usability and Human Factors Unit 4c Human Factors and Healthcare

  2. Mechanism: Time Description: Insufficient time to perform tasks safely, apply safe practices, or monitor patients, and may reduce their communication with physicians. Examples: Little time to double-check medications Mechanism: Motivation Description: Dissatisfied with job, thus affecting their motivation for high-quality performance. Examples: Frustration and negative attitude toward job Mechanism: Stress and burnout Description: Stress and burnout, which can have a negative impact on their performance. Examples: Reduced physical and cognitive resources to perform adequately Mechanism: Errors in decision making (attention) Description: Contribute to errors, such as slips and lapses or mistakes. Examples: Forgetting to administer medications Mechanism: Systemic/organizational impact Description: Could affect the safety of care provided by another nurse. Examples: A charge nurse may not be available to help other nurses with their patients when needed. Effects of Heavy Nursing Workload Carayon, Ayse P. Gurses Health IT Workforce Curriculum Version 1.0/Fall 2010

  3. Mental Workload • Multidimensional construct • Task demands • Expectations regarding the quality of performance • Person effort • Can vary across persons and situations • Difficult to measure Health IT Workforce Curriculum Version 1.0/Fall 2010

  4. NASA Task Load Index • A multi-dimensional rating procedure • Provides overall workload score based on a weighted average of ratings on 6 subscales: • Mental demands • Physical demands • Temporal demands • Own performance • Effort • Frustration Health IT Workforce Curriculum Version 1.0/Fall 2010

  5. MENTAL DEMAND: Low/High How much mental & perceptual activity was required (e.g., thinking, deciding, calculating, remembering, looking, searching, etc.)? Was the task easy or demanding, simple or complex, exacting or forgiving? PHYSICAL DEMAND: Low/High How much physical activity was required (e.g., pushing, pulling, turning, controlling, activating, etc.)? Was the task easy or demanding, slow or brisk, slack or strenuous, restful or laborious? TEMPORAL DEMAND: Low/High How much time pressure did you feel due to the rate or pace at which the tasks or task elements occurred? Was the pace slow and leisurely or rapid and frantic? NASA TLX Index:Rating Scale Definitions Health IT Workforce Curriculum Version 1.0/Fall 2010

  6. EFFORT: Low/High How hard did you have to work (mentally and physically) to accomplish your level of performance? PERFORMANCE: Good/Poor How successful do you think you were in accomplishing the goals of the task set by the experimenter (or yourself)? How satisfied were you with your performance in accomplishing these goals? FRUSTRATION LEVEL: Low/High How insecure, discouraged, irritated, stressed and annoyed versus secure, gratified, content, relaxed and complacent did you feel during the task? NASA TLX Index:Rating Scale Definitions (cont.) Health IT Workforce Curriculum Version 1.0/Fall 2010

  7. Medical Devices • Healthcare products, excluding drugs, which are used for human beings for the purpose of prevention, diagnosis, monitoring, treatment or alleviation of an illness • Center for Devices and Radiological Health, a division of the Food and Drug Administration • Common source of medical error • Operator error (incorrectly entering a drug cartridge concentration) • Patient error • Mechanical problems • 60% deaths & serious injuries attributed to operator error Health IT Workforce Curriculum Version 1.0/Fall 2010

  8. Patient Controlled Analgesics • Method of pain relief which uses disposable or electronic infusion devices and allows patients to self-administer analgesic drugs as required • Patients determine when and how much medication they receive • Abbott Lifecare PCA Plus II is the Markey leader • Used in more than 22 million patients Health IT Workforce Curriculum Version 1.0/Fall 2010

  9. Lin, Isla, Doniz et al (1998) • Purpose: redesign a PCA user interface according to HF techniques and principles • Improve efficiency and safety • Cognitive task analysis was used to evaluate and redesign the system • Experiment involving 12 student nurses programming the device Health IT Workforce Curriculum Version 1.0/Fall 2010

  10. CTA Findings • Structure of many subtasks in programming sequence is unnecessarily complex • No global view of decision process • Lack of external representation of dialog structure • No overview of how many parameters • Order sequence • Steps that have been completed and those that remain • Misleading visual grouping of controls • Limited amount of feedback on small screen Health IT Workforce Curriculum Version 1.0/Fall 2010

  11. Redesign of Interface System structure simplified by minimizing the number of message display screens Choices presented in parallel rather than serially Health IT Workforce Curriculum Version 1.0/Fall 2010

  12. Programming the new interface was 15% faster The average workload rating for the old interface was twice as high New interface led to 10 errors as compared to 20 for the old one Medical equipment can be made safer and more efficient by adopting human factors design principles Experimental Evaluation Health IT Workforce Curriculum Version 1.0/Fall 2010

  13. Mobile Health Devices • Handheld devices used in healthcare context by clinician, patient or health consumer • Palm PDAs, Pocket PC, Smart phones (Treo 650) and Blackberries • ePocrates, LexiDrugs, Up-to-Date, PalmCIS • Mobile Patient Monitoring, Glucowatch, Electronic Health Diaries, & advanced function glucose meters • Improve information access • Enhance workflow • Communication • Promote evidence-based decision making & empower patients • Lack of a stable interaction paradigm, especially on patient side Health IT Workforce Curriculum Version 1.0/Fall 2010

  14. UltraSmart Meter • Hierarchical menu • Nonlinear/tangled • Max depth of 5 • Breadth 2-8 (items on a single menu) • Input: button press Health IT Workforce Curriculum Version 1.0/Fall 2010

  15. Hierarchical Menu Systems • Flow of control between human and device • Interactive style provides visible options to user • Structure of system can be fairly transparent • Constrained path of options • May require minimal training • Learning by exploring menu structure • Breadth-depth tradeoffs Health IT Workforce Curriculum Version 1.0/Fall 2010

  16. Objectives of Study • Usability and learnability of LifeScan UltraSmart • Identify aspects of device facilitate or impede productive use • Determine whether older adults could develop basic competency (learnability) • Autonomously perform or learn to perform the range of tasks through experience and/or reading the instructional materials • Characterize prerequisite competencies, knowledge and skills • Robust Mental Model of System Health IT Workforce Curriculum Version 1.0/Fall 2010

  17. Mental representation of how things work Anticipate events Reason about outcomes Project backwards from event to explain Try to reconstruct episodes from memory Running of a model corresponds to a process of mental simulation Generate possible future states of system For example, “if I click OK on this button, what will happen next”? Temporal and spatial reasoning Mental Models Health IT Workforce Curriculum Version 1.0/Fall 2010

  18. Older adults had inferior mental models of phone menu than younger adults (Ziefle & Bay, 2004) Shallower notion of menu’s depth Lack of understanding of hierarchical representation associated with poor performance Lack of a mental model can lead to disorientation in menu selection tasks Repeatedly open the same node Follow suboptimal paths Increase time to locate information Mental Model of Cell Phone Health IT Workforce Curriculum Version 1.0/Fall 2010

  19. Cognitive task analysis Performed by 3 coders Usability Testing with 5 older adults Two sessions video and audio taped Adults were given a week to learn to use the glucose meter Glucose Meter Usability Evaluation Health IT Workforce Curriculum Version 1.0/Fall 2010

  20. All subjects experienced significant problems in the first session Data entry tasks Demonstrated degree of improvement in second session Highly variable Subjects exhibited trial and error Perseverated through fruitless searches Wrong place Summary of Usability Testing Health IT Workforce Curriculum Version 1.0/Fall 2010

  21. Limited visibility of system state Inadequate prompts Not informative guiding subjects to next step Errors result from following the wrong path Error correction—returning to prior state is nontrivial Confusing task-action mappings Observed Problems Health IT Workforce Curriculum Version 1.0/Fall 2010

  22. Conclusions • UltraSmart™ offers wide range of resources to support self-management in patient with diabetes • Steep learning curve, especially for older adults • Most would experience difficulty in developing a sufficiently robust mental model to negotiate menu structure • Taxing on Memory • Difficult design problem • Empirical testing can yield more effective design solutions Health IT Workforce Curriculum Version 1.0/Fall 2010

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