Human Error
Reducing Errors: More Knowledge in the world: Visibility, Clues, Affordances, feedback, Mapping, forcing function
Reducing Errors: Screen: Undo, confirmation box, Modes, text boxes,
1: Normans 7 Stages of Action
framework for account for how error may arise from interactingwith technology
Goal, Intent, Action Spec, Execution, WORLD, perception, interpret, evaluate.
GULFS of execution/evaluation
Slips
Most errors are slipsSkilled behaviourLack of attention1 focus of attentionUnconciousEasy to uncover
Capture
Frequently done activity takes charge
Description
Internal description of intended action not suffiently preciseUsually correct action, wrong object. e.g. OJ in bowl of cereal
Mode Error
Watch. Run. Reset
Mistakes
Arise from the inappropriate choice of a goal
correct execution of incorrect action sequence
Post-completion errors
photocopier, ATM machine, filling petrol
Dont fill up working memory, should be OK
Endsleys model of situation Awareness
Perception of elements in current situation
Comprehension of situation
Projection of future system status