In 1970, Dr. William Haddon wrote a brilliant editorial that changed forever how we evaluate accidents and other failures in complex systems. The paper was titled, On the Escape of Tigers: An Ecological Note, and it looked at accidents through an etiological rather than descriptive approach. The work was immediately applied to automotive and aviation safety, beginning the enormous reduction in accidents in both fields that continues to this day. In 1990, Dr. James T. Reason published his first work on the role of barriers to sequential failure, and how they fail in truly catastrophic accidents. Together, their combined work forms the basis for much of the best practice for risk mitigation in the automotive, airline, oil & gas and healthcare industries. In this article, I take a look at the failed efforts to control the Ebola outbreak relative to the concepts of Drs. Haddon and Reason.

1. On the Escape of Tigers & Other Public Health Hazards
Considering the Ebola Outbreak in Haddon’s Matrix and Reason’s Swiss Cheese Model
October 16, 2014
Wes Chapman
Preface: In 1970, Dr. William Haddon wrote a brilliant editorial that changed forever how we
evaluate accidents and other failures in complex systems. The paper was titled, On the Escape of
Tigers: An Ecological Note, and it looked at accidents through an etiological rather than
descriptive approach. The work was immediately applied to automotive and aviation safety,
beginning the enormous reduction in accidents in both fields that continues to this day. In 1990,
Dr. James T. Reason published his first work on the role of barriers to sequential failure, and
how they fail in truly catastrophic accidents. Together, their combined work forms the basis for
much of the best practice for risk mitigation in the automotive, airline, oil & gas and healthcare
industries. In this article, I take a look at the failed efforts to control the Ebola outbreak relative
to the concepts of Drs. Haddon and Reason.
Escaping Tiger

2. Haddon’s Strategies and Matrix
Haddon focused his original work on accident prevention, specifically focusing on the reduction
in the amount and structural impact of energy released in a harmful way in an accident. He
promulgated 10 strategies specifically targeted at this goal (see table below). The first four of
these strategies were designed to be implemented before an accident or other untoward outcome
(“pre-event”) to prevent events from happening or minimize the potential negative outcome
(“effect”), the second four strategies are design to protect the party subject to the effect (“host”)
in the course of the event, and the final two were designed to mitigate the negative consequences
post event. Reducing these to a more generalized format we get:
Strategy
Number
Strategy Examples
(Ebola strategies bold)
1 Prevent creation of the
hazard
Ban 3-wheel ATVs, restrict access to explosives,
Design effective Ebola strategy
2 Reduce the amount of the
hazard
Limit pills per container, decrease water
temperature, strict reductions on travel to and
from areas impacted by the virus
3 Prevent release of the hazard Improved brakes, puncture resistant gas tanks,
Quarantines, travel limitations
4 Alter release of the hazard Blister packaging on pills, public health
restrictions of travel for potentially infected
patients
5 Separate person and hazard
in time and space
Child restraints, Quarantines, travel restrictions
6 Place barrier between person
and hazard
Bike helmets, pool fences, Protective clothing &
gear for care givers
7 Modify basic qualities of the
hazard
Breakaway light poles, Protective clothing &
gear for potentially infected patients
8 Strengthen resistance to the
hazard
Earthquake building codes, Special hospital units
for Ebola patients
9 Detect quickly Smoke detectors, Effective blood tests and
screening based on physical characteristics
10 Repair the damage EMS, treatment & rehabilitation, Effective and
timely treatment for Ebola patients
Adapted from slides by Carolyn Fowler, PhD
What makes Haddon’s strategies so compelling is their common sense simplicity, and that they
are fundamentally hopeful; we can alter the frequency and impact of terrible events through
simple and thoughtful actions. Haddon started a revolution in accident prevention by looking at
the causes of accidents and the effects of accidents on victims. These techniques have been
broadly adopted by regulatory authorities around the world, with a long term trend in the
reduction in both number of accidents and resulting injuries and fatalities. It is a method for
optimists, and it really works.

3. Reasons to be Optimistic about Airline Safety
Happy Motoring

4. When later reduced to practice, these strategies were combined into a matrix format.
Influencing Factors
Environment
Strategies
Numbered
Human Agent &
Carrier
Physical Social
1-4 Pre-Event
5-8 Event
9-10 Post Event
Will an event - with the potential to cause
injury occur?
Will an injury, disease or death occur?
What will the outcome be?
Adapted from slide presentation by Carolyn Fowler, PhD
It is instructive to look at the use of Haddon’s Matrix and related tools in the control of the
SARS (Severe Acute Respiratory Syndrome) outbreak in Toronto in the time period of February
to July of 2003. There are a couple of important differences between SARS and Ebola that are
worth noting from the outset. On first blush, SARS is much more communicable (being capable
of airborne transmission), and Ebola is much more fatal (50% fatality rates in Ebola vs. less than
10% for SARS). A slightly deeper examination of the facts suggests that in both cases, these are
primarily nosocomial infections, and that the vast amount of risk of both infection and
transmission lies at the patient/caregiver interface. This was clearly the case in SARS (although
not immediately expected), and the early evidence in the US and Europe certainly points to this
interface as the greatest point of risk for Ebola.
The Haddon Matrix & SARS Hospital Infection Control
Environment
Human Agent & Carrier
(Vector)
Physical and Social
Pre-
Event
1) Staff Training in infection
control, 2) Case mix of patients,
3) Surveillance for SARS by
health care providers, 4) Public
health risk communication
1) Level of contagiousness, 2)
Incubation period, 3) Subclinical
infection potential, 4) Lethality, 5)
Potential modes of transmission
1) Employee awareness of daily
infection control practice, 2) Staff
adherence to infection directives and
protocols, 3) Risk communication to
staff, 4) Budget allocations 5) Plans for
surge requirements, 6) Proximity to
borders, airports and access points, 7)
Availability of Protective gear, 8)
Infection control checklists and forms,
9) Hospital infection control
infrastructure, 10) Lab facilities

5. Event 1) Mental health for staff during
event, 2) Staff adherence to
infection controls, 3) Isolation and
quarantine implementation, 4)
Risk communication to staff and
patients.
1) Modes of dissemination of
virus during actual outbreak.
1) Hospital surge capacity, 2) Trust in
administration crisis management
performance, 3) Availability of
designated SARS hospitals, 4) Budget,
5) Communication network and
capacity, 6) Effective incident
command system, 7) Crisis command
center, 8) Efficiency of medication and
equipment delivery, 9) Positive bias
toward healthcare providers and media
accuracy, 10) Accurate and appropriate
messages to staff and patients, 11)
Moral support to healthcare
community, 12) Patient and family
compliance.
Post
Event
1) Risk communication, 2) Post-mortem
management, 3)
Psychology of post-event reaction,
4) Surveillance
1) persistence of agent in the
environment
1) Decontamination, 2) messaging, 3)
Government financial support, 4)
Restoration of stockpiled medication
and equipment, 5) Mental health
support, 6) economic impact on
affected community.
Source: Environmental health Perspectives, May 2005; 113(5): 561-566
The current Ebola outbreak began in March of this year and now totals 8,997 cases in 7 countries
(WHO bulletin 10/15/2014), dwarfing the next largest (425 cases in Uganda in 2000), of the 22
outbreaks since 1976. This is fundamentally a different scale and risk profile than the world has
witnessed since the SARS outbreak in 2003. It is unclear if the US, the EU or any member of the
G20 has made any special preparations to deal with the Ebola outbreak in the 7 months since it
began.
The control of SARS in Toronto ultimately required a ratio of 100 persons quarantined for every
confirmed case. In Canada alone, this was a total of 23,000 people in quarantine during the
course of the crisis. The premature declaration of victory in the SARS case, resulted in what was
in reality back-to-back pandemics, with a doubling of the cost of illness, lives and economic loss.
Based on the SARS Matrix as an example, and the facts and circumstances of the current Ebola
outbreak, it is worth taking a minute to sketch out an ideal response matrix, and then compare it
to the actual response – at least as far as it has been made public.
Ebola Pandemic – an Ideal Haddon Matrix
Environment
Human Agent & Carrier
(Vector)
Physical and Social
Pre-
Event
1) Direct and permanent
intervention in West
Africa, 2) Extensive drug
research and testing, 3)
1) Ebola is moderately
contagious, with a long
and variable incubation
period, is highly lethal
1) Education is key to public
health in the endemic
countries, 2) Mass
elimination of other

6. Education regarding risks
in animal transmission.
and is easily confused
with other diseases –
active testing and public
health are a requirement,
2) Every attempt must be
made to support curative
therapies and vaccines.
mammalian hosts is a
necessity, 3) Alternative
foods must be available, 4)
Development of
multinational response teams,
5) Stockpiling of equipment
and supplies, 6) Checklists
and extensive “in-country”
training, 7) Rapid response
for burial training and
practice in-country.
Event 1) Mental health for staff
during event, 2) Staff
adherence to infection
controls, 3) Isolation and
quarantine
implementation, 4) Risk
communication to staff
and patients.
1) Modes of
dissemination of virus
during actual outbreak
must be weakened and
eliminated, 2) Every
effort must be made to
limit dispersion of virus,
3) Healthcare workers are
particularly vulnerable to
contagion and need
special prophylactic
therapy where available.
1) Hospital surge capacity, 2)
Trust in administration crisis
management performance, 3)
Availability of designated
Ebola hospitals, 4) Budget, 5)
Communication network and
capacity, 6) Effective
incident command system, 7)
Crisis command center, 8)
Efficiency of medication and
equipment delivery, 9)
Positive bias toward
healthcare providers and
media accuracy, 10) Accurate
and appropriate messages to
staff and patients, 11) Moral
support to healthcare
community, 12) Patient and
family compliance.
Post
Event
1) Risk communication,
2) Post-mortem
management, 3)
Psychology of post-event
reaction, 4) Surveillance,
5) rapid return to pre-event
priorities
1) Persistence of agent in
the environment must be
eliminated wherever
possible to prevent the
double pandemic seen in
SARS.
1) Decontamination, 2)
messaging, 3) Government
financial support, 4)
Restoration of stockpiled
medication and equipment, 5)
Mental health support, 6)
economic impact on affected
community.

7. Ebola Pandemic – Actual Haddon Matrix to date
Environment
Human Agent & Carrier
(Vector)
Physical and Social
Pre-
Event
1) No meaningful or
successful strategy or
intervention, 2) Limited
drug research and testing,
3) Limited education
regarding risks in animal
transmission.
1) Ebola is moderately
contagious, with a long
and variable incubation
period, is highly lethal
and is easily confused
with other diseases –
despite this, no testing
and public health took
place, 2) No meaningful
attempt was made to
support curative therapies
and vaccines.
1) No Education in the
endemic countries, 2) No
systematic elimination of
other mammalian hosts, 3)
No alternative foods
available, 4) No development
of multinational response
teams, 5) Limited stockpiling
of equipment and supplies, 6)
No plans or “in-country”
training, 7) No cultural
changes.
Event 1) Mass confusion and in
action at the government
level. Mental health for
staff during event
ignored, 2) Infection
controls incorrect or not
specified, 3) Isolation and
quarantine
implementation late,
ineffective or non-existent,
4) No risk
communication to staff
and patients.
1) Modes of
dissemination of virus
during actual outbreak
neither weakened nor
eliminated, 2) No effort
made to limit dispersion
of virus, 3) Healthcare
workers are particularly
vulnerable to contagion –
grossly inadequate
training and protective
gear.
1) No hospital surge
capacity, 2) No trust in
administration crisis
management performance, 3)
No designated Ebola
hospitals, 4) Budget?, 5)
Communication network and
capacity wholly inadequate,
6) Ineffective incident
command system, 7) No
crisis command center, 8)
Efficiency of medication and
equipment delivery?, 9)
Positive bias toward
healthcare providers and
media accuracy?, 10)
Inaccurate and inappropriate
messages to staff and

8. patients, 11) Limited moral
support to healthcare
community, 12) No patient
and family compliance, 13)
Command and control turned
over to untrained political
representative, 14) Legal and
financial protection afforded
all quarantined persons at
Federal, State and local
levels.
Post
Event
? 1) Persistence of agent in
the environment must be
eliminated wherever
possible to prevent the
double pandemic seen in
SARS.
?
The entire response US to the Ebola crisis has been done without an articulated strategy,
seemingly responding to political imperatives rather than public health best practice. None of the
obvious strategies or methods that would fit Haddon’s 10 strategic categories has been
employed, and the discourse has taken an alarming political tone. The appointment of Ron Klain,
a political operative and lawyer as administrative chief of the effort begs the question of
credentials, and is certain to further politicize this public health fiasco.
The motivations for sending 3,000 US troops to aid in the Ebola fight is equally mystifying. Our
military is just exiting two decade long wars, and is now being drawn back into further conflict
with ISIS. The putative purpose of this deployment is to build treatment facilities and operate
mobile labs. Surely there are contractors more capable and with fewer agenda conflicts than the
101 Airborne. Sending untrained and poorly equipped US troops in to fight Ebola may be
politically expedient, but I struggle to understand how it fits into any of Haddon’s strategic
framework.
It is interesting to note that Nigeria, a poor West African neighbor to the primarily impacted
countries (Guinea, Sierra Leone and Liberia) successfully turned back Ebola using a well-articulated
and systematically applied strategy that did not include armed combatants. Nigeria’s
Emergency Operations Center sat down with representatives from the World Health
Organization, UNICEF, CDC, Doctors Without Borders and the Red Cross and designed a plan
focused on four teams:

9. 1) A point-of-entry team to monitor and screen passengers entering and departing the
country,
2) An information dissemination team,
3) A case management team, and
4) A contact-tracing group to track down, monitor and quarantine people who had been in
contact with patients suffering with active Ebola.
And it did involve closing the borders.
Ebola virus – the new target of the 101st Airborne
Reason’s Swiss Cheese Model and a Just Culture
James T. Reason is the father of Swiss Cheese Human Error model. This model is based on the
concept that 90% of errors are caused by systemic (latent) rather than simple human factors
(active). Models based on blame, normally miss the fundamental element of passive failure of
accident prevention barriers – much like lining up the holes in Swiss cheese.

10. Combining these work of Haddon and Reason, we get Haddon’s strategies as the slices of cheese
(barriers to failure), and failure occurring when the holes line up, due to chance, poor planning or
systematic strategic failure. Reason proposed a concept of a “Just Culture” as an integral part of
the model of Human Error. Reason’s human Error Model postulates that the vast majority of
errors happen despite the good intentions of the person “causing” the error. In Reason’s just
culture, failed systems rather than failed people are normally the cause of errors, and we need to
investigate how to improve systems rather than blame and punish people if we want to improve
outcomes.

11. Considerations of the US Response to Ebola
Relative to Haddon’s strategies and matrix, the US failed to have any viable strategy for dealing
with Ebola either before or after the outbreak. Prior to the outbreak, we took no steps to combat
the virus through vaccines or drugs, and did nothing to reduce the contact between the virus and
human hosts. This is consistent with the cold blooded calculus that this is a strictly African
problem and of no direct concern to the US, but the spread of the arrival of Ebola in the Dallas
proves this to be short sighted and stupid (as well as callous).
Relative to Reason’s Swiss Cheese model, the barriers to the spread of Ebola that existed prior to
the outbreak were few and full of holes. No vaccine, and no effective drug therapies were
developed, and no coordinated response was initiated when the disease first took root in March.
When the disease finally arrived in the US, we had no training and no protective clothing for our
front line medical staffs.
Our Nation’s response to date gives not even the slightest thought to the plight of people forced
to stop their lives and go into isolation or quarantine because of innocent exposure to the virus.
The forced isolation of quarantine can result in loss of jobs and income, and there is not a single
discussion on any front regarding protecting these people – which will only influence them to
avoid quarantine. This is a national disgrace, and the antithesis of just culture.
The arrival of Ebola into the heartland of America did nothing to stimulate a viable strategic
response. The response of sending armed troops to battle a virus in Africa seems silly, except
when considered as a political rather than a public health action. The best research that I have
found indicates that cutting off flights from the afflicted nations would prevent the spread of the
virus by up to 8 weeks, but when considered politically it is apparently untenable.
The intra-outbreak excellence shown in Toronto by quarantine of patients (as well as potentially
impacted people), has been totally ignored in our country; where we put our potentially infected
people on airplanes and fly them around the country – approved by the CDC. Finally, when the
public has finally had enough, we put a political operative in charge – a man with no background
in public health.
My Grandmother used to say that God watches out for fools and drunks – by her criteria we
should be able to depend on divine intervention in this crisis – it’s as good as any strategy that
we’ve had to date.