Human Factors Issues

1. Human Factors Issues Chapter 8

3. What is Human Factors? • Application of the scientific knowledge of human capabilities and limitations to the design of systems and equipment to produce products with the most efficient, safe, effective, and reliable operation

4. Human Factors • Interface points • Environment • Skill level of user • Interaction between: • Human element • Hardware element • Software element Refrigerator Example

5. Human Element • Memory • Long term • Short term • Thinking and reasoning • Visual perception • Dialogue construction • Individual skill level • Individual sophistication

6. Size limitations Location of controls Possible user training Compatibility with other equipment Hardware Element Control knobs/switches Potential need for portability Display area

7. Simple, reliable data entry Displays must not be overcrowded Software Element Feedback to users Menu driven Dialogue must be jargon-free

8. Human Factors Process • Analytic process that focuses on device objectives • Design and development process that converts results of analyses into detailed equipment features • Test and evaluation process which verifies that development process satisfies constraints

9. Steps in Human Factors Process • Planning • Analysis • Conduct user studies • Observations • Interviews • Focus groups • Task analysis • Benchmark usability tests • User profile • Setup advisory panel Crucial Pieces of Human Factors Process

10. Safety • Should reflect system and personnel safety factors • Failures • Fail safe • Failure indications • Standards- ANSI, AAMI, ISO

11. Documentation • Written to meet needs of various target populations • Study capability and information needs of documentation users • Mental abilities • Physical abilities • Previous experience • Understanding of general operation • Special needs of environment Attempt to avoid this!

12. Anthropometry • Science of measuring human body and its parts and functional capacities • Range of values: 5th percentile female to 95th percentile male • Functional dimensions • Psychological elements • Workstation design considerations

14. Labeling • Labels should be clear and direct • Controls, displays, and other equipment that must be located should be clearly marked • Receptacles and connectors should be marked with intended function or connection • Hazard warnings should be prominent

15. Labeling?

16. Software • Every user input should consistently produce some perceptible response from the computer • Log-on should be automatically completed before any operation • Allow for orderly shutdown in case of failure

17. Data Entry • Consistent data entry transactions • Minimize user input actions • Feedback to user about acceptance or rejection of an entry • Ability to change entry after it has been added

18. Feedback • Present status, information, confirmation, and verification throughout the interaction • Standby should be accompanied by ‘WAIT’ message • Feedback should be self-explanatory

19. Prompts • Commands, error messages, system capabilities, and procedures should be explained with prompts or help instructions • Missing data/aborting changes should be prompted • Factual and informative dialogue • Displayed in standardized area

20. Defaults • Currently defined default values should be provides and automatically displayed • User should be prompted for acceptance of defaults • Users should be able to set their own default