To Err is Human Owen Brennan

January 13th, 2018 – Hawaii, USA

75%-95% of industrial accidents are human error No official guidance on how to reverse a false alert 38 minutes elapsed before same system sent out a safety broadcast Wrong option chosen on drop-down menu Miscommunication, thought it was a real crisis During day-shift/night-shift switch Script included line “exercise, exercise, exercise” but also included, “THIS IS NOT A DRILL” (sorta like saying, “What I am about to say isn’t true don’t listen to me, OH MY GOD RUN THIS IS NOT A DRILL”)

Description/similarity slips Mistakes Action-Based Capture Slips Description/similarity slips Mode errors Memory-lapse Errors Rule-based Knowledge-based Memory-Lapse

Errors Any deviance from “appropriate” behavior Norman’s definition “Appropriate” does not need to be known General term for all wrong actions Two sub-categories: slips and mistakes

Description/similarity slips Mistakes Action-Based Capture Slips Description/similarity slips Mode errors Memory-lapse Errors Rule-based Knowledge-based Memory-Lapse

Slips The action performed was not the action that was intended Meant to do the “appropriate” thing Within the seven stages of the action cycle, slips occur in the execution or interpret/perceive stages Two sub-categories: action based, memory lapse

Description/similarity slips Mistakes Action-Based Capture Slips Description/similarity slips Mode errors Memory-lapse Errors Rule-based Knowledge-based Memory-Lapse

Action-based slips Occur in the specify, perform, perceive, or interpret stages of the action cycle Three subcategories: capture slips, description-similarity slips, mode errors

Capture slips When performing an activity, a similar activity gets performed instead of the desired activity. The capturing activity is usually one done more recently or more frequently Examples?

Description-similarity slips Item acted on is similar to, but different from, the target item Sometimes caused by ambiguous description Examples?

Mode error slips When there are several modes, or states, that a device could be in, and the user acts upon the wrong mode. Buttons that can do multiple things Not enough space for many buttons leads to a need for modes Signaling what mode the device is currently in would help Examples?

Description/similarity slips Mistakes Action-Based Capture Slips Description/similarity slips Mode errors Memory-lapse Errors Rule-based Knowledge-based Memory-Lapse

Memory lapse slips Cause of many more errors Often caused by interruptions, or too much time between start and finish of desired action Ways to combat: Less steps Reminders Forcing function Examples?

Description/similarity slips Mistakes Action-Based Capture Slips Description/similarity slips Mode errors Memory-lapse Errors Rule-based Knowledge-based Memory-Lapse

Mistakes The wrong goal was established or the wrong plan was formed From then on it does not matter how well the actions are performed Three subcategories: rule-based, knowledge-based, memory-lapse

Rule based mistakes Mistake involving rules, dealing with familiar/prepared situations Multiple ways in which this can occur The situation is misinterpreted so the wrong rule is invoked The rule itself is faulty Correct rule is invoked, but the outcome is incorrectly evaluated Examples?

Knowledge based mistakes Occurs in novel situations, so there are no rules to invoke New procedures must be devised Helped by good conceptual models, manuals, or AI help. Examples?

Memory-Lapse Mistakes Similar to before, but these memory-lapses cause the goals and plans to be wrong Helped by making all the relevant information available to the user Examples?

Description/similarity slips Mistakes Action-based Capture slips Description/similarity slips Mode errors Memory-lapse Errors Rule-based Knowledge-based

Handling Errors 5 Why? Method: asking why a bunch to get to the root Poka-Yoke method: physical obstructions/indicators to prevent errors Encourage reporting errors, punish not reporting errors Discovering errors quickly limits their damage Feedback helps with slips Mistakes are harder to detect

Designing for error Constraints block potential errors Make it easy for users to undo errors Make it easy for users to know if they have made an error Confirmation/error message Make it easy to resume after an interruption Prevent possible interruptions Provide well-designed warning signals (usually not the answer though)

Minimizing slips Make sure controls are distinct, both in appearance and position Eliminate most/all modes if possible If not, display all the modes with the current mode distinct from the rest Reminders for infrequent tasks Initial steps should be dissimilar Training

Design principles Lessen the amount of knowledge that has to be in the head, keep it in the world Use natural and artificial restraints to exploit how users interact with a device Provide feedforward (what options are available) and feedback (make the results apparent)

Navigation Bloopers Let the user know where they are, where they can go, and where they have been

Some blooper examples Window does not have a title Window title appears on multiple different pages Window title does not match where it was linked from Distracting buttons/links No way to backtrack Self-links Too many dialogue boxes Multiple search boxes Poor search result browsing/noisy search results

Back to Hawaii… What type(s) of errors occurred? How could the errors have been prevented? How could the errors have been better handled?

Bib https://gizmodo.com/fcc-explains-how-that-nuke-alert-happened-in- hawaii-1822554911 Don Norman, The Design of Everyday Things, Chapter 5 Jeff Johnson, GUI Bloopers 2.0, Chapter 3