How Resilience Engineering Can Transform NASA’s Approach
to Risky Decision Making
David Woods, Professor
Institute for Ergonomics
The Ohio State University
The Future of NASA
Committee on Commerce, Science and Transportation, John McCain, Chair
October 29, 2003
To look forward and envision NASA as a high reliability organization, we need first to
look back with clarity unobscured by hindsight bias. Admiral Gehman and the Columbia
Accident Investigation Board (CAIB) found the hole in the wing was produced not simply
by debris, but by holes in organizational decision making. The factors that produced the
holes in decision making are not unique to today’s NASA or limited to the Shuttle
program, but are generic vulnerabilities that have contributed to other failures and
tragedies across other complex industrial settings.
For 24 years my research has examined the intersection of human decision making,
computers, and high risk complex situations from nuclear power emergencies to highly
automated cockpits to medical decision making, and specifically has included studies of
how space mission operation centers handle anomalies.
CAIB’s investigation shows how NASA failed to balance safety risks with intense
production pressure. As a result, this accident matches a classic pattern—a drift
toward failure as defenses erode in the face of production pressure. When this pattern
is combined with a fragmented problem solving process that is missing cross checks
and unable to see the big picture, the result is an organization that cannot see its own
blind spots about risks. Further, NASA was unable to revise its assessment of the risks
it faced and the effectiveness of its countermeasures against those risks as new
evidence accumulated. What makes safety/production tradeoffs so insidious is that
evidence of risks become invisible to people working hard to produce under pressure
so that safety margins erodes over time.
As an organizational accident Columbia shows the need for organizations to monitor
their own practices and decision processes to detect when they are beginning to drift
toward safety boundaries. The critical role for the safety group within the organization
is to monitor the organization itself—to measure organizational risk—the risk that the
organization is operating nearer to safety boundaries than it realizes.
In studying tragedies such as Columbia, we have also found that failure creates windows
for rapid learning and improvement in organizations. Seizing the opportunity to learn is
the responsibility leaders owe to the people and families whose sacrifice and suffering
was required to make the holes in the organization’s decision making visible to all. NASA
and Congress now have the opportunity to transform the culture and operation of all of
NASA (Shuttle, ISS, and space science missions), and by example transform other high
The target is to help organizations maintain high safety despite production pressure.
This is the topic of the newly emerging field of Resilience Engineering which uses the
insights from research on failures in complex systems, including organizational
contributors to risk, and the factors that affect human performance to provide practical
systems engineering tools to manage risk proactively.
NASA can use the emerging techniques of Resilience Engineering to balance the
competing demands for very high safety with real time pressures for efficiency and
production. By following the recommendations of the CAIB to thoroughly re-design its
safety organization and provide for an independent technical authority, NASA can
provide a model for high reliability organizational decision making.
The Trouble with Hindsight
The past seems incredible, the future implausible.1
Hindsight bias is a psychological effect that leads people to misinterpret the
conclusions of accident investigations.2 Often the first question people ask about the
decision making leading up to an accident such as Columbia is, “why did NASA
continue flying the Shuttle with a known problem…?” (The known problem refers to the
dangers of debris striking and damaging the Shuttle wing during takeoff which the CAIB
identified as the physical cause of the accident.)
As soon as the question is posed in this way, it is easy to be trapped into
oversimplifying the situation and the uncertainties involved before the outcome is
1 Woods, D.D. and Cook, R.I. (2002). Nine Steps to Move Forward from Error. Cognition, Technology, and
Work, 4(2): 137-144.
2 The hindsight bias is a well reproduced research finding relevant to accident analysis and reactions to
failure. Knowledge of outcome biases our judgment about the processes that led up to that outcome.
In the typical study, two groups of judges are asked to evaluate the performance of an individual or team.
Both groups are shown the same behavior; the only difference is that one group of judges are told the
episode ended in a poor outcome; while other groups of judges are told that the outcome was successful
or neutral. Judges in the group told of the negative outcome consistently assess the performance of
humans in the story as being flawed in contrast with the group told that the outcome was successful.
Surprisingly, this hindsight bias is present even if the judges are told beforehand that the outcome
knowledge may influence their judgment.
Hindsight is not foresight. After an accident, we know all of the critical information and knowledge needed
to understand what happened. But that knowledge is not available to the participants before the fact. In
looking back we tend to oversimplify the situation the actual practitioners faced, and this tends to block our
ability to see the deeper story behind the label human error.
known.3 After-the-fact “the past seems incredible,” hence NASA managers sound
irrational or negligent in their approach to obvious risks. However, before any accident
has occurred and while the organization is under pressure to meet schedule or increase
efficiency, potential warning flags are overlooked or re-interpreted since the potential
“future looks implausible.” For example, the signs of Shuttle tile damage became an
issue of orbiter turn around time and not a flight risk.
Because it is difficult to disregard “20/20 hindsight”, it is easy to play the classic blame
game, define a “bad” organization as the culprit, and stop. When this occurs, the same
difficulties that led to the Columbia accident will go unrecognized in other programs
and in other organizations.
The CAIB worked hard to overcome hindsight bias and uncover the breakdown in
organizational decision making that led to the accident. All organizations can
misbalance safety risks with pressure for efficiency. It is difficult to sacrifice today’s real
production goals to consider uncertain evidence of possible future risks. The heart of
the difficulty is that it is most critical to invest resources to follow up on potential safety
risks when the organization is least able to afford the diversion of resources due to
pressure for efficiency or throughput.
Five General Patterns Present in Columbia
The CAIB report identifies a variety of contributors to the accident. These factors have
been seen before in other accidents.4 Focusing on the general patterns present in this
particular accident helps guide the process of envisioning the future of NASA as a high
Classic patterns also seen in other accidents and research results include:
• Drift toward failure as defenses erode in the face of production pressure.
• An organization that takes past success as a reason for confidence instead of
investing in anticipating the changing potential for failure.
• Fragmented problem solving process that clouds the big picture.
• Failure to revise assessments as new evidence accumulates.
• Breakdowns at the boundaries of organizational units that impedes
communication and coordination.
1. The basic classic pattern in this accident is—Drift toward failure as defenses
erode in the face of production pressure.
My colleague, Erik Hollnagel in 2002, captured the heart of the Columbia accident when
he commented on other accidents:
3 See S. Dekker’s The Field Guide to Human Error Investigations. Ashgate, 2002.
4 Hollnagel, E. (1993). Human Reliability Analysis: Context and Control. London: Academic Press.
If anything is unreasonable, it is the requirement to be both efficient and
thorough at the same time – or rather to be thorough when with hindsight it was
wrong to be efficient.
Hindsight bias, by oversimplifying the situation people face before outcome is known,
often hides tradeoffs between multiple goals. The analysis in the CAIB report provides
the general context of a tighter squeeze on production goals creating strong incentives
to downplay schedule disruptions. With shrinking time/resources available, safety
margins were likewise shrinking in ways which the organization couldn’t see.
Goal tradeoffs often proceed gradually as pressure leads to a narrowing focus on some
goals while obscuring the tradeoff with other goals. This process usually happens
when acute goals like production/efficiency take precedence over chronic goals like
safety. If uncertain “warning” signs always lead to sacrifices on schedule and efficiency,
how can any organization operate within reasonable parameters or meet stakeholder
The paradox of production/safety conflicts is: safety investments are most important
when least affordable. It is precisely at points of intensifying production pressure that
extra investments for managing safety risks are most critical.
The NASA of the future will need a means to recognize when the side effects of
production pressure may be increasing safety risks and under those circumstances
develop a means to add investments to safety issues at the very time when the
organization is most squeezed on resources and time.
2. Another general pattern identified in Columbia is that an organization takes past
success as a reason for confidence instead of digging deeper to see underlying
One component in the drift process is the interpretation of past “success”. The
absence of failure is taken as positive indication that hazards are not present or that
countermeasures are effective. An organization usually is unable to change its model of
itself unless and until overwhelming evidence accumulates that demands revising the
model. This is a guarantee that the organization will tend to learn late, that is, revise its
model of risk only after serious events occur. An effective safety organization assumes
its model of risks and countermeasures is fragile and seeks out evidence to revise and
update this model.5 To seek out such information means the organization is willing to
expose its blemishes.
During the drift toward failure leading to the Columbia accident a mis-assessment took
hold that resisted revision (that is, the mis-assessment that foam strikes pose only a
maintenance and not a risk to orbiter safety). It is not simply that the assessment was
wrong, but the inability to re-evaluate the assessment and re-examine evidence about
risks is troubling.
5 Rochlin, G. I. (1999). Safe operation as a social construct. Ergonomics, 42 (11), 1549-1560.
The missed opportunities to revise and update the organization’s model of the riskiness
of foam events seem to be consistent with what I have found in other cases of failure of
foresight. I have described this discounting of evidence as “distancing through
differencing” whereby those reviewing new evidence or incidents focus on differences,
real and imagined, between the place, people, organization and circumstances where
an incident happens and their own context. By focusing on the differences, people see
no lessons for their own operation and practices or only narrow well bounded
Ominously, this distancing through differencing that occurred throughout the build up to
the final Columbia mission can be repeated in the future as organizations and groups
look at the analysis and lessons from this accident and the CAIB report. Others in the
future can easily look at the CAIB conclusions and deny their relevance to their situation
by emphasizing differences (e.g., my technical topic is different, my managers are
different, we are more dedicated and careful about safety, we have already addressed
that specific deficiency).
One general principle to promote organizational learning in NASA is—Do not discard
other events because they appear on the surface to be dissimilar. Rather, every event,
no matter how dissimilar on the surface, contains information about underlying general
patterns that help create foresight about potential risks before failure or harm occurs.
The NASA of the future will have a safety organization that question NASA’s own model
of the risks it faces and the countermeasures deployed. Such review and re-
assessment will help NASA find places where it has underestimated the potential for
trouble and revise its approach to create safety.
3. Another general pattern identified in Columbia is a fragmented problem solving
process that clouds the big picture.
During Columbia there was a fragmented view of what was known about the strike and
its potential implications. There was no place or person who had a complete and
coherent view of the analysis of the foam strike event including the gaps and
uncertainties in the data or analysis to that point. It is striking that people used what
looked like technical analyses to justify previously reached conclusions, instead of
using technical analyses to test tentative hypotheses (e.g., CAIB report, p. 126 1st
People were making decisions about what did or did not pose a risk on very shaky or
absent technical data and analysis, and critically, they couldn’t see their decisions
rested on shaky grounds (e.g., the memos on p. 141, 142 of he CAIB report illustrate the
shallow, off hand assessments posing for and substituting for careful analysis).
The breakdown or absence of cross-checks is also striking. Cross checks on the
rationale for decisions is a critical part of good organizational decision making. Yet no
cross checks were in place to detect, question or challenge the specific flaws in the
rationale, and no one noted that cross-checks were missing.
There are examples of organizations that avoid this fragmentation problem. Ironically,
one of them is teamwork in NASA’s own Mission Control which has a successful record
of analyzing and handling anomalies.6 In particular, the Flight Director and his or her
team practice identifying and handling anomalies through simulated situations. Note
that shrinking budgets lead to pressure to reduce training investments (the amount of
practice, the quality of the simulated situations, and the number or breadth of people
who go through the simulations sessions can all decline).
The fragmentation of problem solving also illustrates Karl Weick’s point7 about how
important it is that high reliability organizations exhibit a “deference to expertise”,
“reluctance to simplify interpretations”, and “preoccupation with potential for failure”
none of which were in operation in NASA’s organizational decision making leading up to
and during Columbia.
The NASA of the future will have a safety organization that ensures that adequate
technical grounds are established and used in organizational decision making.
To accomplish this for NASA, the safety organization will need to define the kinds of
anomalies to be practiced as well as who should participates in those simulation
training sessions. The value of such training depends critically on designing a diverse
set of anomalous scenarios with detailed attention to how they unfold. By monitoring
performance in these simulated training cases, the safety personnel are able assess the
quality of organizational decision making.
4. The fourth pattern in Columbia is a Failure to revise assessments as new
I first studied this pattern in nuclear power emergencies 20 plus years ago.8 What was
interesting in the data then was how difficult it is to revise a mis-assessment or to revise
a once plausible assessment as new evidence comes in. This finding has been
reinforced in subsequent studies in different settings.
The crux is to notice the information that changes past models of risk and calls into
question the effectiveness of previous risk reduction actions, without having to wait for
complete clear cut evidence. If revision only occurs when evidence is overwhelming,
there is a grave risk of an organization acting too risky and finding out only from near
misses, serious incidents, or even actual harm. Instead, the practice of revising
assessments of risks needs to be an ongoing process. In this process of continuing re-
6 For example, see: E.S. Patterson, J.C. Watts-Perotti, D.D. Woods. Voice Loops as Coordination Aids in
Space Shuttle Mission Control. Computer Supported Cooperative Work, 8, 353—371, 1999. J.C. Watts,
D.D. Woods, E.S. Patterson. Functionally Distributed Coordination during Anomaly Response in Space
Shuttle Mission Control. Proceedings of Human Interaction with Complex Systems, IEEE Computer
Society Press, Los Alamitos, CA, 1996. Patterson, E.S., and Woods, D.D. (2001). Shift changes, updates,
and the on-call model in space shuttle mission control. Computer Supported Cooperative Work, 10(3-4),
7 Weick, K. E., Sutcliffe, K. M. and Obstfeld, D. (1999). Organizing for High Reliability: Processes of
Collective Mindfulness. Research in Organizational Behavior, Volume 21, pp. 81-123.
8 D.D. Woods, J. O'Brien, and L.F. Hanes. Human factors challenges in process control: The case of
nuclear power plants. In G. Salvendy, editor, Handbook of Human Factors/Ergonomics, Wiley, New York,
evaluation, the working assumption is that risks are changing or evidence of risks has
Research consistently shows that revising assessments successfully requires a new
way of looking at previous facts. We provide this “fresh” view:
(a) by bringing in people new to the situation
(b) through interactions across diverse groups with diverse knowledge and tools,
(c) through new visualizations which capture the big picture and re-organize data into
One constructive action is to develop the collaborative inter-changes that generate
fresh points of view or that produce challenges to basic assumptions. This cross
checking process is an important part of how NASA mission control responds to
anomalies. One can also capture and display indicators of safety margin to help people
see when circumstances or organizational decisions are pushing the system closer to
the edge of the safety envelope.
What is so disappointing about NASA’s organizational decision making is that the
correct diagnosis of production/safety tradeoffs and useful recommendations for
organizational change were noted in 2000. The Mars Climate Orbiter report of March
13, 2000 clearly depicts how the pressure for production and to be ‘better’ on several
dimensions led to management accepting riskier and riskier decisions. This report
recommended many organizational changes similar to the CAIB. A slow and weak
response to the previous independent board report was a missed opportunity to
improve organizational decision making in NASA.
The NASA of the future will have a safety organization that provides “fresh” views on
risks to help NASA see its own blind spots and question its conventional assumptions
about safety risks.
5. Finally, the Columbia accident brings to the fore another pattern: Breakdowns
at the boundaries of organizational units.
The CAIB notes how a kind of catch 22 was operating in which the people charged to
analyze the anomaly were unable to generate any definitive traction and in which the
management was trapped in a stance shaped by production pressure that views such
events as turn around issues. This effect of an ‘anomaly in limbo’ seems to emerge
only at boundaries of different organizations that do not have mechanisms for
constructive interplay. It is here that we see the operation of the generalization that in
risky judgments we have to defer to those with technical expertise (and the necessity to
set up a problem solving process that engages those practiced at recognizing
anomalies in the event).
This pattern points to the need for mechanisms that create effective overlap across
different organizational units and to avoid simply staying inside the chain of command
mentality (though such overlap can be seen as inefficient when the organization is
under severe cost pressure).
The NASA of the future will have a safety organization with the technical expertise and
authority to enhance coordination across the normal chain of command.
Resilience Engineering is built on insights derived from the above five patterns.
Resilience Engineering is concerned with assessing organizational risk, that is the risk
that holes in organizational decision making will produce unrecognized drift toward
While assessing technical hazards is one kind of input into Resilience Engineering, the
goal is to monitor organizational decision making. For example, Resilience Engineering
would monitor evidence that effective cross checks are well-integrated when risky
decisions are made or would serve as a check on how well the organization is
practicing the handling of simulated anomalies (what kind of anomalies, who is involved
in making decisions).
Other dimensions of organizational risk include the commitment of the management to
balance the acute pressures of production with the chronic pressures of protection.
Their willingness to invest in safety and to allocate resources to safety improvement in a
timely, proactive manner, despite pressures on production and efficiency, are key
factors in ensuring a resilient organization.
The degree to which the reporting of safety concerns and problems is truly open and
encouraged provides another significant source of resilience within the organization.
Assessing the organization’s response to incidents indicates if there is a learning culture
or a culture of denial. Other dimensions include:
• Preparedness/Anticipation: is the organization proactive in picking up on
evidence of developing problems versus only reacting after problems become
• Opacity/Observability—does the organization monitors safety boundaries and
recognize how close it is to ‘the edge’ in terms of degraded defenses and
barriers? To what extent is information about safety concerns widely distributed
throughout the organization at all levels versus closely held by a few individuals?
• Flexibility/Stiffness—how does the organization adapt to change, disruptions,
9 For initial background on the emergence of resilience engineering see Rasmussen, J. Risk Management,
Adaptation, and Design for Safety. In B. Brehmer and N.-E. Sahlin (Eds.) Future Risks and Risk
Management. Kluwer Academic, Dordrecht, 1994. Rasmussen, J. (1997). Risk Management in a Dynamic
Society: A Modelling Problem. Safety Science, 27, 183-213. Reason, J. (2001). Assessing the Resilience
of Health Care Systems to the Risk of Patient Mishaps. Carthy, J., de Leval, M. R. and Reason, J. T. (2001).
Institutional Resilience in Healthcare Systems. Quality in Health Care, 10: 29-32. Weick, K. E. and
Sutcliffe, K. M. (2001). Managing the unexpected : assuring high performance in an age of complexity. San
Francisco : Jossey-Bass. Cook, R. I., Render, M. L. and Woods, D.D. (2000). Gaps in the continuity of
care and progress on patient safety. British Medical Journal, 320, 791-794, March 18, 2000. Woods, D. D.
and Shattuck, L. G. (2000). Distance supervision—local action given the potential for surprise Cognition,
Technology and Work, 2, 86-96. Leveson, N. G. (in press). A New Accident Model for Engineering Safer
Systems. Safety Science. Roberts, K.H., Desai, V., and Madsen, P. (in press) Work Life and Resilience in
High Reliability Organizations. In E. Kossek and S. Lambert (Eds.) Work and Life Integration Mahwah: NJ:
• Revise/Fixated—how does the organization update its model of vulnerabilities
and the effectiveness of countermeasures over time?
The NASA of the future will create a new safety organization and culture that is skilled
at the three basics of Resilience Engineering:
(1) detecting signs of increasing organizational risk, especially when production
pressures are intense or increasing;
(2) having the resources and authority to make extra investments in safety at precisely
these times when it appears least affordable;
(3) having a means to recognize when and where to make targeted investments to
control rising signs of organizational risk and re-balance the safety and production
These mechanisms will produce an organization that creates foresight about changing
risks before failures occur.
Redesigning NASA for Safety:
An Independent, Involved, and Informed Safety Organization
One traditional dilemma for safety organizations is the problem of “cold water and an
empty gun.” Safety organizations raise questions which stop progress on production
goals—the “cold water.” Yet when line organizations ask for help on how to address the
safety concerns, while being responsive to production issues, the safety organization
has little to contribute—the “empty gun.” As a result, the safety organization fails to
better balance the safety/production tradeoff in the long run. In the short run following
a failure, the safety organization is emboldened to raise safety issues, but in the longer
run the memory of the previous failure fades, production pressures dominate, and the
drift processes operate unchecked (as has happened in NASA before Columbia and
appears to be happening again with respect to ISS).
Re-shuffling personnel and re-tuning the existing safety organization does not meet the
spirit of the CAIB recommendations. First, a new leadership team well versed in
organizational decision making, systems approaches to safety, and human factors in
complex systems needs to be assembled and empowered.
Second, the key target for the new safety organization is to monitor and balance the
tradeoff of production pressure and risk. To do this the leadership team needs to
implement a program for managing organizational risk—detecting emerging ‘holes’ in
organizational decision making—based on advancing the techniques of Resilience
Third, the new safety organization needs the resources and authority to achieve the
three “I’s” of an effective safety organization (independence, involvement, information):
• provide an independent voice that challenges conventional assumptions within
• constructive involvement in targeted but everyday organizational decision
making (for example, ownership of technical standards, waiver granting,
readiness reviews, and anomaly definition).
• actively generate information about how the organization is actually operating,
especially to be able to gather accurate information about weaknesses in the
Safety organizations must achieve independence enough to question the normal
organizational decision making. At best the relationship between the safety organization
and NASA senior management will be one of constructive tension. Inevitably, there will
be periods where senior management tries to dominate the safety organization.
Congress needs to provide the safety organization the tools to resist these predictable
episodes by providing funding directly and independent from NASA headquarters.
Similarly, to achieve independence, the safety leadership team needs to be chosen and
accountable to designees of Congress, not directly to the NASA administrator or NASA
Safety organizations must be involved in enough everyday organizational activities to
have a finger on the pulse of the organization and to be seen as a constructive part of
how NASA balances safety and production goals. This means the new safety
organization needs to control a set of resources and the authority to decide how to
invest these resources to help line organizations provide high safety while
accommodating production goals. For example, the safety organization could decide
to invest and develop new anomaly response training programs when it detects holes in
organizational decision making processes.
In general, safety organizations risk becoming information limited as they can be
shunted aside from real organizational decisions, kept at a distance from the actual
work processes, and kept busy tabulating irrelevant counts when their activities are
seen as a threat by line management (for example, the ‘cold water’ problem).
Independent, involved and informed—these three properties of an effective safety
organization are closely connected and mutually reinforcing.
Unfortunately, it sometimes takes tragedies such as Columbia to create windows of
opportunity for rapid learning and improvement. It is our responsibility to seize the
opportunity created at such cost to lead change. Congress can energize the creation of
an independent, involved and informed safety organization for NASA. The NASA of the
future can become the model of an organization that escapes a trap where production
pressure erodes safety margins.
The future NASA will balance the goals of both high productivity and ultra-high safety
given the uncertainty of changing risks and certainty of continued pressure for efficient
and high performance. To carry out this dynamic balancing act requires a new safety
organization designed and empowered to be independent, involved and informed. The
safety organization will use the tools of Resilience Engineering to monitor for “holes” in
organizational decision making and to detect when the organization is moving closer to
failure boundaries than it is aware. Together these processes will create foresight about
the changing patterns of risk before failure and harm occurs.