= Error Handling =

Key points

* humans are the most unpredictable part of any system and therefore the most
  difficult to model for design
* humans have higher failure rates unde rhigh sctress levels, but are more
  flexible in recovering form emergegeny situations and the last hope in a
  potential disaster
* there is a tradoff between making the HCI easy and intutive, and ensuring the
  system safety is not comprimised by a cocky operator

== Types of human error ==

* slips
  * genuine human error when operating equipment
  * action is not what was intended
* lapses
  * spacing out
* mistakes
  * more serious consequences
  * intention is not appropriate
* Violations
  * purposful breaking things

== Slips ==

=== types of slips/errors ===

* capture errors start of task sequence
  * drive to store, but wound up driving to work
* description errors two tasks are very similar
  * throwing laundry in toilet
* data-driven errors counting
  * Meant one number but used another
* associative activation errors
  * internal associations between tasks, IE fruendian slips
* loss-of-activation errors
  * forgetting why you started a task

=== prevent slips ===

* minimize number of steps by allowing existence of constraints
* provide clear visible or audible reminders/sugesstions
* utilize forcing functions
  * IE required step to complete a process
* minimize chance of error in the design
* perform sensibility checks
* allow for reversal of certain actions
* feedback or error discovery and corection

== Error recovery ==

* attempt to automatically identify the error and provide a solution
* user will first guess what has happened
* user will then try to work backwards to find a solution
* user may not have the knowledge to fix system. user then trys to find a new
  method to do the same thing