Group 2

• • Can be defined in terms of either the action or the consequences of the action.
  • Cannot be defined by considering human performance in isolation, but have to be defined in reference to human interactions or expectations.

  Error
• • Behavior that is without conscious control.
  • Very well learned highly automated preconscious procedures for perceiving features in the environment and performing actions.

  Skill-based
• • Proposed a three-level hierarchy:

  Rasmussen (1986)
• • Behaviour that is with conscious control, in familiar situations, using stored rules or procedures.
  • Learned recognition of situations, association of situations with tasks, application of stored rules for actions and problem-solving steps in particular situations.

  Rule-based
• • Behaviour that is exhibited in unfamiliar situations.
  • Thinking using knowledge to identify situations, set goals and make decisions, and plan actions.

  Knowledge-based
• • Errors at this level arise from speed-accuracy trade-offs, intrinsic variability of the human operator, capture by motor schemata etc.
  • Errors occur due to fallibility in perception, attention, memory or execution.

  Skill-based slips
• • Errors at this level involve failures in the selection or application of problem-solving rules.
  • Errors occur due to application of wrong rules, incorrect recall of rules, reliance on an under-specified cue set and interference from familiar rules.

  Rule-based mistakes
• • Errors at this level arise due to the “trial and error” learning involved in novel situations.
  • Errors occur due to the hypothesis testing process, resource limitations or interference in functional reasoning due to false analogies.

  Knowledge-based mistakes
• • Is making the wrong decision about what to do.
  • The action may go as planned, but the plan itself is wrong.

  Mistakes
• • The plan for the action may be correct, but the actions do not go as planned.
  • Is a failure to execute a decision correctly

  Slip
• • Types of errors:

  1. Mistakes
  2. Slips
• • Categorization of action Slips

  1. Capture Slip
  2. Double Capture Slip
  3. Omission Slip
  4. Loss of Activation Slip
  5. Description Slip
  6. Associative Activation Slip
  7. Perceptual Confusion Slip
  8. Reverse Schema Slip
  9. Repetition of Action Slip
  10. Crosstalk Slip (Concurrent)
  11. Crosstalk Slip (Sequential)
• Categorization of action Slips

  • Automatic activation of a well-learned routine that overrides the current intended activity.

  Capture Slip
• Categorization of action Slips

  • Unintended activation of a related strong action schema.

  Double Capture Slip
• Categorization of action Slips

  • Action specification lost before triggering action; due to interruptions.

  Omission Slip
• Categorization of action Slips

  • Goal is lost before generation of action specification.

  Loss of Activation Slip
• Categorization of action Slips

  • Incomplete or ambiguous specification of intention that is similar to a familiar intention.

  Description Slip
• Categorization of action Slips

  • Activation of similar but incorrect action schema

  Associative Activation Slip
• Categorization of action Slips

  • Ex. (Realise I just moisturised my face with hair cream. My eyebrows look fab.)

  Perceptual Confusion Slip
• Categorization of action Slips

  • Reverse action schema overwrites forward action schema.

  Reverse Schema Slip
• Categorization of action Slips

  • Repetition of correctly performed action.

  Repetition of Action Slip
• Categorization of action Slips

  • Action components are exchanged between two or more concurrent actions.

  Crosstalk Slip (Concurrent)
• Categorization of action Slips

  • Action components are exchanged between two or more sequential actions.

  Crosstalk Slip (Sequential)
• • Refers to twelve of the most common human error preconditions, or conditions that can act as precursors, to accidents or incidents.
  • These twelve elements influence people to make mistakes.

  The Dirty Dozen (Dupont)
• • The Dirty Dozen:

  1. Lack of Communication
  2. Lack of Teamwork
  3. Lack of Awareness
  4. Lack of Assertiveness
  5. Lack of Knowledge
  6. Lack of Resources
  7. Norms
  8. Fatigue
  9. Distraction
  10. Stress
  11. Complacency
  12. Pressure
• • Propose that the effort should be to maximize the discovery of error (error capture), to make it easier to recover from error (error recovery), and to minimize the incidence of error.

  Lewis and Norman (1995)
• • Possible system responses:
  • Gag
  • Warn
  • Do nothing
  • Self-correct
  • Let's talk about it
  • teach me
• Possible system responses

  • prevent the user from continuing.

  Gag
• Possible system responses

  • Beeps, text messages.

  Warn
• Possible system responses

  • Clicking on a disabled control provides no visible change.

  Do nothing
• Possible system responses

  • Word processor auto-correct function.

  Self-correct
• Possible system responses

  • The system responds by initiating a dialogue with the user, co-operative problem solving.

  Let's talk about it
• Possible system responses

  • The system asks for further clarification.

  Teach me
• • A useful error message is one that not only tells the user what went wrong, but also provides some information on how to take the right action.

  Error Messages
• • Feedback on the effects of actions should be provided to the user.
  • Such feedback facilitates error recovery by supporting functional understanding and also helps knowledge-based monitoring.

  Feedback
• • Interface design principles that can be applied to minimise the consequences of human error include 11:

  1. Ensure consistency across interfaces.
  2. Provide good conceptual models or metaphors
  3. Reduce or account for mode, capture or description errors
  4. Provide visibility through affordances
  5. Provide appropriate constraints and mapping
  6. Reduce the gap between the gulf or execution and the gulf of evaluation
  7. Provide appropriate communication and feedback
  8. Facilitate multiple activities
  9. Understand cultural biases
  10. Use colour
  11. Provide online help