The discussion continues with chapter 5. (After some time ). This chapter had some heavy content and took some time to complete. Expecting to see some interesting thoughts/questions/comments.
The chapter begins with don debating that even though the majority of accidents are blamed on human error, it is actually down to bad design. When investigating the cause of an accident it is important not to stop at the human error but go beyond and see what caused the human error. One method to find the root cause analysis is the ‘5 Whys’ where you keep on digging in a cause and effect manner. Another model of analysis is the Swiss cheese model which takes into account that there are multiple causes of an accident and you need to determine each of these causes.
Don classifies errors into Slips and Mistakes. Slips are when you have the correct plan in mind but falter in execution. Mistakes happen when you have the wrong plan in mind and therefore the execution is doomed to fail. Slips are further classified into action slips and memory slips. Mistakes are classified into rule based mistakes, knowledge based mistakes and memory based mistakes. Slips frequently happen in digital products with people clicking the wrong target for their action or forgetting an action. Mistakes frequently occur when there is not enough knowledge provided for the user to make the correct decision.
Why do people make these errors? Interruptions, multitasking, mental limitations, social/institutional pressure and deliberate violations.
How can we minimize errors through design? Adding constraints, providing ‘Undo’, providing timely confirmation & error messages, provide required knowlege for operation in the real world, show feedforward information, avoiding similar targets/procedures for distinct actions.
The ‘Undo’ option seems a preferred method today with products opting out of an additional confirmation while providing the undo feature.
“Physical limitations are well understood by designers; mental limitations are greatly misunderstood.”
“Error occurs for many reasons. The most common is in the nature of the tasks and procedures that require people to behave in unnatural ways”
“We should deal with error by embracing it, by seeking to understand the causes and ensuring they do not happen again”
Some discussion points
- Examples you have come across for error prone designs and designs which have done well to handle errors
- How do we take the mental limitations of the user into the design? (eg. Fatigue)