SCSC.uk logo
SCSC.uk logo
SCSC - Newsletter
SCSC - Newsletter

Log in to SCSC.uk

Please log in using either your email address or your membership number.

Register on SCSC.uk

Please register with your name, email address, password and email preferences. You will be sent an email to verify the address.

   No thanks
   No thanks

Reset your password

Please enter the email address used for your account. A temporary password will be emailed to you.

 September 2007

Safety Systems

Volume 17 
Number 1 
 ❰ previouscontents next ❱

Book review:

Safety Cases and Safety Reports: Meaning, Motivation And Management
by Richard Maguire
Published by Ashgate Publishing Limited
Hardback, pp 176, £55.00

Review by Phil Williams

The title of the book promises an insight into the subtleties of presenting a compelling case that a system is tolerably safe for its intended use. The abstract on the rear cover refers to safety cases and safety case reports. I wondered whether the different wording between the title and rear cover was significant. The distinction between the case and a report providing a snapshot of its status has been captured in standards such as Defence Standard 00-56 for many years, yet frequently those intending to refer to the report take a shortened approach and refer simply to ‘the safety case’, thus losing the distinction. The distinction between a safety report and a safety case report is, in my experience, even more significant. Am I being too pedantic? I’ll proceed with an open mind and offer the benefit of the doubt.

I looked forward to reading an informed text that would reassert the distinction, explaining the differences in meaning and motivation behind them, and defining how their creation and maintenance would be managed. I expected this to take us through a journey detailing what was required for a safety case, maybe looking at different lifecycle phases and requirements for different industries. Maybe even addressing the relationship up the supply chain, looking at how safety evidence from organisations providing components, equipment or subsystems into larger systems would be managed. Could it address the distinction between the designer and operator viewpoints and even cover in its scope safety cases for ‘systems-of-systems’?

Having pondered what I might find within the book, I thought I’d check who the book is targeted at. Nothing on the rear cover, the preface or introductory chapter commented on the intended readership, and as I continued through reading the book I kept coming back to this question ... who is this book aimed at?

On inspecting the table of contents it is apparent that the book covers a significant scope in the management of safety. Chapter headings cover concepts of accidents, the language of safety, the safety management system, safety boundaries, targets, techniques and tools, as well as those that explicitly mentioned safety case in their title. Whilst these are all valid topics for addressing within a safety case, it was starting to look like too much for a relatively small book on this topic.

Reading further it becomes clear that the book will not deal with any of these topics in depth. There are many discussion points from the author’s experience, and issues to consider, and a wide range of source material is referenced and quoted from. I found a few insights that I thought could be useful, such as in Chapter 6 – ‘Setting a safety boundary’ – where consideration of different domains may reveal interesting factors, but I got few answers from the book on what I might do once I’d considered these topics. The content of some chapters seemed too close to topics covered in others. For example, the question posed in Chapter 4 – ‘The purpose of a safety case’ – ‘Why are you constructing a safety case?’ and that in Chapter 5 –‘ The requirement for a safety case’ – ‘Why do you need a safety case anyway?’

The early chapters of the book deal with definitions and seem to conclude that whilst various different sector and country safety standards use different words to describe their reporting requirements, they all essentially come down to the same thing in requiring a safety case, by any other name. I was uncomfortable with this and suspect that there is a significant difference in ownership and utilisation of say, a UK Defence Standard 00- 56 safety case and a US Military Standard 882 safety assessment report. I’ve no doubt there are topics here to keep the York safety electronic mailing list busy for months.

Much of the content of the book provides topics and points that should be considered when establishing a safety management system and a programme of work to deliver a safety case. In many cases the decisions that come from deliberating these topics will be outside an individual’s influence and there is little guidance as to who should be considering these topics, and at what lifecycle point. For example, Chapter 5 discusses the relative merits of goal-based and prescriptive standards. This discussion is really only relevant to those who set the standards. More relevant for most would be discussion on the different ways in which these styles of standard should be addressed in creating a safety case.

Chapter 7 – ‘Measuring safety performance’ – describes risk criteria, and provides an example on how to calibrate a risk matrix. However, factors such as societal perception (who’s at risk? how many injuries/fatalities may occur in one accident?) are left to later chapters for discussion, and not referenced. I found myself disagreeing with some of the detail in a number of the chapters, and being confused by the message in some of the others.

When I did finally get on to the later chapters on safety cases I was disappointed to find that the distinction between safety cases and safety case reports had melted away and that there was no indepth discussion on phasing, stakeholder viewpoint, or other aspects I’d hoped for. The potentially useful consideration of ‘the IT-based safety case’ was simplistic and didn’t deal with the issue that I worry about most: how can you be sure that the reader sees what you intended them to see if you’re using a tool/browser to render the narration of the case?

Overall I found the book to be too broad to cover the topic of the title in depth, yet incomplete in covering all aspects of safety management. I found the content of the chapters to be disjointed and in some cases repetitive. I will take away a few nuggets of thought that I may be able to use in the future, but the effort to extract them was too great for me to be able to recommend this book to peers. I believe this all comes back to my original question: who is this book targeted at? It gives insufficient guidance for a novice and insufficient depth for an expert.

Phil Williams may be contacted at

 ❰ previouscontents next ❱