Human Failure Modes
Dr. Azad M. Madni
Professor , Epstein Department of Industrial and Systems Engineering
Director, SAE Program
Co-Director, CSSE
March 6, 2012
Copyright © 2012 Azad Madni
Outline
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Human Failure Modes
Demanding Systems Requirements
Implications for Humans
Evolving Human Roles
Systems Engineering Mindset
The Remarkable Human Brain
Human Error Sources
Potential Remedies and Opportunities
Copyright © 2012 Azad Madni
Human Failure
■ Comprises
human errors, which are unintentional behaviors
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violations, which are willful disregard of rules and regulations
■ Human errors fall into specific categories
slips, lapses of memory
mistakes in following rules and procedures
mistakes in understanding
Copyright © 2012 Azad Madni
Demanding System Requirements
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Adaptability
Reconfigurability
Composability
Resilience
These requirements pose formidable challenges for
humans that work with and within complex systems
Copyright © 2012 Azad Madni
Implications for Humans
■ System adaptability implies changing contexts and potential
changes to human-system interactions
■ System reconfigurability implies potential changes to human
roles and human-system function allocation
■ System resilience implies potential dynamic changes to
human role and attendant changes to cognitive load
■ System composability (as in SoSs) implies potential changes
in collaborators (lack of shared conceptual model)
These changes can increase likelihood of human error.
Copyright © 2012 Azad Madni
Evolving Human Roles
■ From that of operator outside
system to that of agent within
an adaptable system
decision maker
supervisor
monitor with override authority
re-assignable participant
(peer, assistant)
These roles require new behaviors.
Copyright © 2012 Azad Madni
Systems Engineering Mindset
• Humans are suboptimal job performers that need to be
shored up and compensated for during task performance
• This perception leads to systems that are inherently
incompatible with human conceptualization of work
• The resulting mismatch inevitability creates human reliability
issues that show up as human error
This mindset fails to capitalize on human ingenuity
Copyright © 2012 Azad Madni
The Remarkable Human Brain
■ Yuor Barin Can Raed This
■ For emaxlpe, it deson’t mttaer in waht oredr the
ltteers in a wrod aepapr, the olny iprmoatnt tihng
is taht the frist and lsat ltteer are in the rghit pcale.
The rset can be a toatl mses and you can sitll raed
it wouthit pobelrm.
■ S1M1L4RLY, Y0UR M1ND 15 R34D1NG 7H15 4U70M471C4LLY
W17H0U7 3V3N 7H1NK1NG 4B0U7 17.
■ How ?
Source: LiveScience.com
Copyright © 2012 Azad Madni
Human Error Sources (Examples)
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Erroneous/Incomplete Mental Model
 often traceable to poor design- results in mistakes
 lack of complete info causes user to make
unwarranted assumptions about system state
 also results from misrecognition of cues/state info
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Drop in Vigilance/Arousal during Monitoring
 occurs with infrequent stimulus leading to
missed cue detection
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Loss of Focus during Task Performance
 results in slips (execution errors) arising from inattention
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Cognitive Overload
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causes: multi-tasking, context switching, decision making under stress
can lead to suboptimal behaviors and human errors (mistakes and slips)
Copyright © 2012 Azad Madni
Key Findings
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Humans change cognitive strategies under overload
Inverted-U relationship: performance & stress
Humans unable to distribute attention under stress
Adaptability of human-in-the-loop system is
upper-bounded by acceptable human error rate
■ System inspectability facilitates human intervention
and avoids having to make erroneous assumptions
■ For robust performance
 need to minimize multitasking and context switching
 employ alerting/automation to monitor and flag rare events
 need to understand cognitive strategies under overload for effective aiding
Copyright © 2012 Azad Madni
Potential Remedies
■ Design human work to avoid multi-tasking and frequent context
switching to the extent possible
■ Assign rare event monitoring to automation or alerting mechanisms
■ Provide decision aiding and performance support for decision
making under stress
■ Design appropriate incentives to counter risk compensation
tendency
■ Employ automation and dynamic function allocation to assure
manageable cognitive load
Most complex problems will require a combination of
many of these remedies.
Copyright © 2012 Azad Madni
Potential Opportunities
■ Exploit human ingenuity and creativity in:
adapting to shifting contexts
generalizing from specifics
recognizing novelty and improvising
aggregating information in the absence of an algorithm
detecting and filling gaps (e.g., in narratives)
Most complex problems will require a combination of
human creativity and ingenuity.
Copyright © 2012 Azad Madni
So,….Is Human Error a Cause or
Consequence?
Thank You
Copyright © 2012 Azad Madni
My References
■ Madni, A.M. “Integrating Humans with Software and Systems: Technical Challenges and a
Research Agenda,” Keynote Presentation, 22nd Annual Systems & Software Technology
Council, Salt Lake City, Utah, April 26–29, 2010.
■ Madni, A.M. “Integrating Humans with Software and Systems: Technical Challenges and a
Research Agenda,” INCOSE Journal of Systems Engineering and, Vol. 13, No. 3, 2010.
■ Madni, A.M. “Integrating Humans with Software and Systems: Technical Challenges and a
Research Agenda,” Keynote Presentation, INCOSE 2010 LA Mini-Conference, Loyola
Marymount University, October 16, 2010.
■ Madni, A.M. “Integrating Humans With and Within Software and Systems: Challenges and
Opportunities,” (Invited Paper) CrossTalk, The Journal of Defense Software Engineering,
May/June 2011, “People Solutions.”
Copyright © 2012 Azad Madni