1. Demystifying Safety Cases: Concepts and
Misconceptions
Dr George Despotou, PhD

2. © 2015
Claims about safety

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A safety case is…
…nothing more than
A convincing explanation (or justification) about why we
should have confidence in a position
– E.g. think of a legal case
In the healthcare services setting
– Why is a service is safe?
• The subject of the safety case scopes its content (resolution)
– A car safety case vs. a motorway safety case
– A medical device safety case vs. a service safety case

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Why?
In many cases service/system developers/operators have
the onus to defend the safety of their products
Need to capture all reasoning and relevant information
Need to communicate this with other stakeholders
– Regulators, public, employees, managers, service designers
– All need to use a common platform

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A safety case is the information vessel for the necessary
discourse that will provide confidence in the service

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Safety cases in high reliability industries

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Can you please convince me?
a) Our staff have undergone expensive training
b) We only hire the best
c) Safety is our first priority
d) We have safety culture
e) We have identified the risks
f) We have introduced controls to the risks
g) We’ve been doing it for years
h) We comply to standards
i) What are you implying? We’re offended

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We are safety conscious
Continuous
training
Procedures Guidelines Metrics Audit Compliance
We already collect a large amount of evidence to support safety but their explanation
needs mores structure

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Safety case elements
Position
Evidence
Argument

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Safety case elements
Position
Evidence
Argument
A&E service acceptably
safe
We have identified the
risks
We have controlled the
risks
By way of checklists
Expected risk vs risk
trends
OK, but how can you
convince me?
OK, but does this really
work?
Counter-evidence?

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Safety case enables evidence based safety
In many industries there has been a move from process based to
evidence based
Process based
– Standards prescribe various degrees of compliance
• Higher degree -> more analyses
– Confidence appealing to rigour of analysis
Evidence based
– Explicit explanation of risks, and controls for their reduction
– Based on collected evidence (qualitative and quantitative)
– Process rigour one type of evidence not complete justification

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Services as systems
Healthcare services as
socio-technical systems
– Service oriented
• Organisation (e.g. process)
• Systems
• People
Example: extract from an
A&E service
SC would argue about
controlling risks for all
elements
Patient look-up
at reception
Register Patient
Request X-ray
Prescribe
antibiotics
Hospital
admission
Other pathways
Other pathways
Patient
management
System
Prescription
System
Nurse
Doctor
Doctor
Phar.

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Arguments
Process
– Right order, performance, guidelines, interaction of steps
IT systems
– Correctness
– Appropriate
• You could have the wrong thing implemented very reliably
People
– Training, competency, procedures, human factors
Organisational
– SMS, standards, culture, feedback, counter-evidence process

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Is that all?
Yes, in terms of the basic concept
Under the hood (among others)
– Arguments are made using propositional logic
• Premises leading to conclusions, which are themselves premises to other conclusions
– Until satisfactory explanation of evidence
– Rules for forming positions and claims
– Strength of evidence framework
• E.g. controlling risk vs removing risk (e.g. dosage checklist vs. dosage checks in EHR)
– Graphical notations making SC more user friendly
– Strategies to form complex arguments
• A flat list or risks is not the most clear argument
– Lifecycle and relation to analyses

15. Misconceptions

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It’ll just…
Safety issues and implicit/explicit controls will exist
regardless of them being (explicitly) documented

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Too expensive…
Safety case provides references to all the logic that
justifies confidence
Information (should) already exists
– Risk assessments, analysis (e.g. Clinical FMEA), controls,
evidence
A SC owner will need some training (but you don’t
really training to read a SC)

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Too big…
Depends on complexity of your reasoning
Safety case structures information that you should have
already produced
Not everything contained in a single document
Viewpoint reports
Summary reports

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It will increase safety…
It will facilitate review
– Clarity
– Brevity (references)
– Focus on different parts for different
stakeholders
– Explicit logic
Makes weaknesses more obvious
– SC guidance asks to look for counterevidence
But you could perfectly well create a
weak case

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Applications?
ISB 0129, 0160 ask for a safety case when IT is introduced
in clinical services
– Mandatory DH ISB standard via CfH
Health Foundation report on transferability from other
industries
Safer clinical systems

21. FAQ article on Safety Cases
http://bit.ly/ZYK425