The world’s smallest HCI problem Paul Cairns. Today’s objectives Basics of human error Error...
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Transcript of The world’s smallest HCI problem Paul Cairns. Today’s objectives Basics of human error Error...
The world’s smallest HCI problem
Paul Cairns
Paul Cairns, ADVT Error
Today’s objectives
Basics of human error Error in HCI Number entry error
18th February, 2014
Paul Cairns, ADVT Error
Errare humanum est
To err is human– #errordiary
So it’s not that interesting Change in perception in 1950s
18th February, 2014
Paul Cairns, ADVT Error
Exercise
Bring to mind an example where something has gone wrong with using a device/system. Whose fault was it?
18th February, 2014
Paul Cairns, ADVT Error
Reason and Rasmussen
Slips– Skill-based
Mistakes– Rule-based, knowledge-based
Violations
18th February, 2014
Paul Cairns, ADVT Error
Exercise: classify
Jumping a red light Adding milk to a black coffee Calling someone by the wrong
name Misreading a recipe and adding a
tablespoon instead of a teaspoon of chilli
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Paul Cairns, ADVT Error
Not so simple
What is an error? Complex, dynamic problems What causes an error?
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Paul Cairns, ADVT Error
Studying error
Low error rates Incomplete cases Ecological validity But errors can be systematic
18th February, 2014
Paul Cairns, ADVT Error
Wason Selection Task
Four cards Each with a letter on one side and
a number on the other Turnover cards to test the rule If there is a vowel on one side
then there is an odd number on the other
18th February, 2014
Paul Cairns, ADVT Error
Wason Selection Task
Four envelopes Each with a country on one side
and perhaps a signature on the other
Turnover cards to test the rule If it is an international address
then it must be signed on the back
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Paul Cairns, ADVT Error
Explanation
Poor reasoning? Poor task? Concreteness? Really erroneous?
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Error in HCI
Patterns in people Devices provoke errors– Task design
Task-action cycle Post completion errors
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Medical errors
10% of all admissions 10% potentially fatal 3rd biggest killer in the UK
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Paul Cairns, ADVT Error
Usual HCI concerns
Task Context Workload Training…
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Simplify: number entry
Read a number Transcribe it into a device Error is any deviation from the
written number Can also measure deviation
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Paul Cairns, ADVT Error
Which device is better?
Numberpad Four-key (Chevron) Five-key Dial
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What do errors look like?
Wiseman – 350 errors No idea! (16%) Wrong digit (13%) Anagram (12%)
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Improving designs
Syntax System 1 vs System 2 Visualising quantity
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Paul Cairns, Number entry in medical devices
Syntax: well-formed numbers
ISMP– Do not use trailing zeros (5 mg, never
5.0 mg).– Use leading zeros for doses less than
one measurement unit (0.3 mg, never .3 mg).
– Units– Font: 0•35
25th May, 2012
CS Open Day, Paul Cairns 21
Regular expressions
Shorthand Describe “strings” of characters Three operations:– Sequence– Iteration, *– Optionality, |
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CS Open Day, Paul Cairns 22
Examples
Let = “A”|… |“Z” Num = “0”| … |“9” LetLet NumNum LetLetLet “Y” Num*
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CS Open Day, Paul Cairns 23
Exercise
Can you come up with a regular expression for ISMP compatible numbers?
29th September, 2012
Paul Cairns, Number entry in medical devices
Checking syntax
Regular expression checker 10-digit keypad Model all numbers with error
rates Halve the out-by-10 errors
25th May, 2012
Paul Cairns, ADVT Error
System 1 vs System 2
Fiction! Cluster of interesting results Diemand-Yauman effect– Fortune favours the bold (and the
italicized)
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Effect in number entry?
TypoMadness study Number entry study Source or Target?
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Paul Cairns, ADVT Error
DY Effect works…
… longitudinally? … acceptably? … in practice?
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Paul Cairns, ADVT Error
Summary
Errors are complex Device design is important Simple tasks reveal the complexity
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Paul Cairns, ADVT Error
ReadingDiemand-Yauman et al. (2011), Cognition, 118(1)Oladimeji, Thimbleby, Cox (2013), Interact 2013Reason, Human ErrorThimbley, Cairns (2010) J. R. Soc. InterfaceWason (1966), Reasoning (or Wikipedia)Wiseman, Cairns, Cox (2011) Proc. of BCS HCI
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