Presenting Uncertainty Clearly: Challenges In
Communicating Geotechnical Risk
Nick SARTAIN, Juliet MIAN and Matthew FREE Arup, UK
Abstract. This paper provides recommended guidelines for communicating geotechnical risk. Geotechnical engineering in
practice is the management of ground-related risks, and geotechnical engineers are good at this. However, they are often less good at communicating these risks to stakeholders who may hold very different perceptions of risk. A review of selected good practice in risk communications from other industries is presented along with lessons that are considered to be applicable to communication of geotechnical risk. The authors draw on their extensive experience in communicating geotechnical risk, ranging from public consultation events for controversial ground engineering projects to working with clients with diverse risk tolerance and risk understanding. Clear, inclusive and participatory risk communication and management is considered essential in such cases.
Keywords. risk, communication, uncertainty, geotechnical risk
1. Introduction
Geotechnical engineering in practice is the management of ground-related risks, and geotechnical engineers are good at this. However, we are often less good at communicating these risks to stakeholders who may hold very different perceptions of them. For example, anxious members of the public may tend to be risk averse and not receptive to the concepts of low probabilities of occurrence, whereas conversely cost-conscious clients may place an emphasis on the low probability of occurrence as justification for cost-savings, without considering the full implications if an event does occur. As geotechnical engineers it is necessary to tread carefully between these two positions to give accurate, consistent and useful advice to all stakeholders.
There exists a broad range of literature on risk management. In this paper we restrict ourselves to a review of selected good practice in risk communications. Lang et al., (2001) emphasize that effective risk communication is an essential part of the implementation of a risk management plan. We have looked at risk communication from other industries to summarize lessons that are considered to be applicable to communication of geotechnical risk.
The authors will also draw on their own good (and bad) experiences in communicating geotechnical risk, ranging from detailed risk analyses with excessive technical jargon to effective public consultation events for controversial ground engineering projects involving a broad range of stakeholders, to working with clients with diverse risk tolerance and risk understanding.
2. Common Problems in Communicating Risk Risk is a very useful concept since it affords experts a method of comparing scenarios to make decisions. A fundamental problem in communicating risk is that because risk is only a concept, it only holds for large populations and therefore doesn’t really exist for specific problems (Blastland and Spiegelhalter, 2013). And because it doesn’t really exist, yet at the same time everyone knows what feels ‘risky’, it is quite common for the same risk to be mean completely different things to different people.
Decisions in geotechnical engineering may impose risks on the public, and so are involuntary from the perspective of those at risk. Involuntary risks should not be compared to © 2015 The authors and IOS Press.
This article is published online with Open Access by IOS Press and distributed under the terms of the Creative Commons Attribution Non-Commercial License.
voluntary risks – for example, the risks due to induced-seismicity compared to flying in an aeroplane or driving a car. A technical expert may need to convey the risk fairly to both the client and to the public, whose perception of the risk is certain to be different. The use of qualitative terms to describe the risk may be helpful since they remove the ‘technicality’ for the lay-person, but will have different meanings for different people. Quantitative terms are more precise, but describing risks using numbers alone is often confusing for many.
Even when using quantitative descriptions, without clear communication over the context of the numbers being used the meaning is open to misinterpretation.
Though there is uncertainty in everything in life, humans are poor at coping with it, and acknowledging uncertainty presents difficulties for both technical and non-technical people. For the technical person, uncertainty adds complexity to analyses and clouds decision-making. In acknowledging uncertainty, an expert is exposed to accusations of lack of knowledge or competence. For the non-technical person uncertainty can lead to confusion as to what course of action is being recommended, mistrust of authority, or to resorting to the intuitive response to the situation whether that is rational or not. A common response is not to communicate the uncertainty or risk at all. For example, a geotechnical design undertaken to the requirements of a modern code of practice implicitly includes a (small) risk of failure. But because this risk is implicit, and everyone can acknowledge that the design was done “to the code” the risk is rarely acknowledged.
The lexicon of risk terminology is also problematic. The words used by experts are the same as those used by the inexpert in everyday use, and they are often used indiscriminately.
3. Errors People Make in Communicating Risk
It is surprisingly common how frequently experts not only encounter the problems described above, but also make the following basic errors:
Loose wording: Having noted that the terminology of risk is used in everyday language
it is very important that experts are consistent and accurate in their choice of words. It is not acceptable to use ‘hazard’ and ‘risk’ interchangeably, nor ‘likelihood’ and ‘risk’ but this is often done. We recommend the consistent use of terminology as presented in ISO 31000:2009.
Frame of reference: Often risk is described with poor (or no) frame of reference, particularly in respect of units. This often makes risks unintelligible. Risks must not just be quoted as percentages and must always have a time frame (for example, what does ‘1% risk of failure of slope’ mean?).
Technical jargon: It is also easy for an expert to slip into technical jargon which can alienate the audience. It is also important to explain technical issues clearly as otherwise the focus of the communication is lost. For example, a discussion on the risk of a slope failure can quickly degenerate into a lecture on the meaning of pore pressures.
Inappropriate comparisons: Many risk situation are difficult to convey, and using a comparison may help to clarify the message. However, comparisons that are inappropriate often make things worse (Sandman, 1987). Perception of risk varies significantly according to many factors (familiarity, voluntary, the age of most affected people, the benefit that is accrued by those affected etc., HSE, 2001, Wright and Rogers, 2014) and any comparison must be sensitive to the perceptions of those being addressed. If they cannot appreciate it as a ‘fair’ comparison, the message will be lost.
4. Review of Best Practice from Other Industries
Much of the written advice on best practice in the communication of risk relates to disaster or significant public health situations (Bouder and Lofstedt, 2010, Sandman, 1987, Lang et al. 2001). The medical professions in particular have learnt significant lessons in the communication of risk (e.g. Kinsella, 1989, describes the mis-communication in the US media in relation to the management of the AIDS crisis).
Increasingly, there is advice on presenting risks to the media, who then interpret the expert opinion for the public (Fox, 2012). A comment made by Sandman (1987) in relation to communicating risk to the media is “Good science pursues abstractions, but good communication looks for examples and images”. His point was that the media need a story, not just facts and numbers, and this is readily transferable to any situation where technical risk needs to be presented to lay-people.
Some other industries attempt to provide a description of their confidence in the assessment of risk. The Intelligence Community provides estimates of risk associated with an event using familiar terms such as ‘probable’, ‘likely’, ‘very likely’ or ‘almost certain’. Additionally, they acknowledge that the assessment is based on information that varies in quality and sourcing, and therefore additional information is provided to provide the confidence in the assessment (e.g. ‘low confidence’). We have used this type of approach in communication of geotechnical risk to date, and propose that as a minimum it is important to acknowledge sources of uncertainty and their impact on the risk.
From the literature a number of common themes are apparent:
x Risk communication is a two-way process between the expert and lay-person. Risk communication should be a dialogue, avoiding confrontation and should not just be the expert delivering their findings.
x Build relationships on trust through frequent dialogues between stakeholders. If necessary involve a highly trusted independent individual, who may be considered unbiased;
x Act rationally and objectively, and base decisions on the best available data and best science;
x Simplify the message, but do not oversimplify;
Finally, when should risk be communicated? There is no single optimum time, it should be a continuous process, as shown in Figure 1 (after Fischhoff and Kadvany, 2011).
5. Risk Communication Examples in Ground Engineering
Since geotechnical engineering is in essence the art of managing ground-related risk, the best practice advocated in the literature is relevant to the day-to-day communications of the practicing geotechnical engineer, and not just to major or particularly hazardous projects.
The following high level examples, from the authors’ professional experience, show a range of circumstances where the communication of risks is important.
Figure 1. Recommended procedure for communicating risk at each stage of the risk management process
Seismic engineering is one of the few branches of civil engineering where an explicit probabilistic approach is routinely used to define the hazard. But even within seismic engineering risk is not discussed as openly as it should be. Just because a building is designed ‘to the code’ does not mean it will not collapse due to a large, very rare, earthquake within its lifetime. Much more pertinently, it certainly does not mean it will not be damaged by a more common earthquake, and the current focus on performance-based design (e.g. the Arup ‘ReDI’ guidance, Arup, 2013), and engaging clients on
the subject of what is acceptable performance for their business, building or facility, seeks to address this.
A Geotechnical Basis of Design is much more than stating the codes that shall be used; it sets out the process by which the geotechnical hazards and uncertainties will be managed throughout the design, construction, operation and even demolition of the scheme, Phear et al (2012). This document should be used to set out the risk strategy for the project and to communicate with the relevant stakeholders the risks that are being taken. This is particularly important when there are elements of the design that are beyond the scope of design codes. The client may be the final arbiter of what level of risk is accepted since they will often be best placed to perform any cost-benefit analyses required.
In the design of temporary works a balance must always be found between cost and safety for temporary works. Clear communication of risks, and the information that is used in risk assessment, between the contractor(s) and both the temporary and permanent works designers is vital.
Public consultations for controversial projects. Members of the public can challenge, and potentially delay a project on the basis of their incomplete knowledge, therefore public consultation should be regarded as a key opportunity for communication.
Where a project is of particular public concern, for example due to its environmental impact (e.g. shale gas or coal bed methane) not only is it important to inform the client of the risk profile of the project, but it is essential that all stakeholders are informed and involved in the identification and assessment of risks (DEFRA, 2011). The public will rightly have concerns over such projects, and it is important to demonstrate that their concerns are being addressed and that they are important to the client. Skillful communication must be used to remove ‘dread’ (UWE, 2014) and to present any residual risks clearly. For example a risk related to subsidence, might be assessed to be low, yet a member of the public might have seen examples of building collapse induced by subsidence. The challenge is to explain the concept of probability, which, in the case of a project causing sufficient subsidence to induce catastrophic collapse, is
extremely low (e.g. Brooks et al. 2006).Complex projects will legitimately lead to a broad range of concerns for members of the public and other stakeholders. It is recommended that knowledge experts are available to respond to a broad range of concerns.
Risks associated with novel construction solutions, as in the case of the Gautrain Rail Link in South Africa (Sartain et al. 2011). This project involved communication of complex issues relating to sinkhole size and frequency and sinkhole/pile interaction, which led to significant potential for cost savings with an associated risk acceptance.For major infrastructure schemes with a formal approvals process, particularly those undertaken as Design and Build projects, the project (cost and programme) risks associated with adopting novel or advanced analysis methods need to be balanced against potential savings in construction and material costs. It is also vital for these projects that geotechnical risks are communicated clearly across the full project team, and between successive designers or contractors, since it is often the case that the team appointed for scheme design will not undertake detailed design, Phear et al. (2012). Care must therefore be taken, through use of risk registers or other means, to ensure consistency and resolution of issues.
Managing existing infrastructure assets such as railway earthworks (e.g. Niewiarowski et al. 2012). Asset managers are often challenged as to why apparently ‘serviceable’ earthworks can fail in extreme rainfall events. Uncertainty of ground conditions, historical construction methods, third party interactions, dependency on drainage assets and ground water conditions, all of which have associated uncertainty, can be challenging to clearly communicate, particularly when there is a perception that these are not getting better with time.
Commercial drivers are important to understand, in the context of construction delays due to hazards in the ground (Chapman 2008), or re-using existing pile foundations for new developments (Anderson et al. 2006), where savings in foundation costs with associated risks to the programme may be far outweighed by the cost of those programme risks in terms of delayed opening for example. Good risk communication is necessary to avoid conflict
situations and to demonstrate best value for clients.
6. Recommended Guidelines
In developing guidelines for practicing engineers on how best to communicate ideas around uncertainty and risk, the first thing to recognize (Mansfield et al., 2012) is that there is no single answer to the question. Each situation is different and requires a different approach, either due to the nature of the risk itself, or to the situation or to the groups of people to whom the risk has to be communicated.
As geotechnical engineers it is our responsibility to make stakeholders (including the public where appropriate) an integral part of the risk management process: we refer to this as Inclusive Risk Management. Appropriate communication at all stages of the process is a critical factor for success. Figure 1 emphasizes the use of communication and the dialogue at each stage of the process (the two way arrows). Repeated communication provides time for stakeholders to consider the issues, to “sleep on it”, and to listen and discuss again, as required.
We recommend that communication starts from the initiation of the risk management process, rather than letting experts undertake their risk assessment alone and announce their conclusions at the end. The ‘Analyze-Decide-Announce-Defend’ approach is a demonstrably ineffective way of working within society.
The guidelines for communicating geotechnical risk presented in this paper are based on a broad range of experience communicating geotechnical risk, including technical reporting, stakeholder engagement and working with clients with diverse risk tolerance, and from a review of good practice from a range of other industries.
We have distilled this down to the following recommendations, which contribute towards an Inclusive Risk Management framework.
1. Remember that probability, statistics and risk are often unintuitive and difficult (Spiegelhalter and Gage, 2014);
2. Understand and respect the inherent biases of your audience. Ensure trust is maintained through impartial, un-emotive and
evidence-based advice to present a neutral case. Acknowledge any potential for bias in your analyses (UWE, 2014);
3. Communicate risk throughout the project, and at each stage of the risk management process Figure 1;
4. Maintain a two-way dialogue on risk throughout, and use this to develop relationships of trust;
5. State the risk in absolute terms, using the most familiar units. If percentages are used be completely clear about what the percentage means If a comparison is used, ensure that the risk is truly comparable to the person affected (avoid comparing voluntary and involuntary risks);
8. Explain (impartially) that there may be benefits as well as consequences to risks. But be careful if none of these benefits apply to those who suffer the potential adverse consequences of the risk;
9. Acknowledge sources of uncertainty, and their impact on the risk, and how these can be treated;
10. Ensure that communication is a simple as necessary, but no simpler, in order to facilitate understanding. Do not use qualitative descriptions to ‘dumb-down’ an analysis;
7. Conclusions
Geotechnical engineers are expert at managing ground-related risk, but until they properly communicate ground-related risks they should expect surprise and complaints whether an event does (with negative impacts) or doesn’t (with a perception of unnecessary costs) materialize.
Communicating risk is challenging for many reasons, from the complexity of the analyses being presented to the widely varying perceptions of risk that exist amongst stakeholders to projects. The recommendations presented in this paper have been found by the authors to be useful in framing conversations around ground risks. It is hoped that they will provide others tasked with managing geotechnical risk with a guide to overcoming the difficulties of communicating these issues.
We leave our final comment to Fischhoff (2009):
“By definition, better risk communication should help its recipients to make better choices. It need not make the communicators’ lives easier…What it should do is to avoid conflicts due to misunderstanding…leading to fewer but better conflicts.”
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