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Risk assessing the complex nature of crowds - The Crowd magazine

Risk assessing the complex nature of crowds

Whether we are aware of it or not, we are continually conducting risk assessments in our everyday life. From crossing the road to walking down steps, subconsciously, we are dynamically assessing the likelihood of a hazard occurring.

Identifying and mitigating risk is the heart of our role in protecting the safety of crowds. With this at the heart of our industry, one would assume that there is a robust and standardised approach to the process. However, reality shows this is not always the case.

Crowds are a complex narrative of mathematics and psychology that require more than one linear approach to managing risks.

In the industry, there are divided opinions on what risk assessment tools are appropriate for the task at hand.

When one pictures a risk assessment, it may take the form of a Probability Impact Graph (PIG)/Risk Matrix, and to many, it is risk management. PIGs are a popular and simplistic method of assessing risk with templates easily accessible online and in print. This format was informally adopted by the event industry from safety management practices of other industries, but do we accept it as fit for purpose?

UK law states that a risk assessment must be completed, but apart from offering guidelines, it does not command what format it must be presented in. Academic research into risk management suggests that first pass risk quantification should be so easy that the usual resistance, based on lack of data with subjective probabilities, is overcome (Chapman and Ward, 2000).

Measuring Risk

Cresswell (2013) states that the fundamental challenge with this approach is that qualitative risk is based on a philosophy that ‘risk = probability x impact’. The flaw in this system is that it gives an average to the risk, which goes against the very nature of risk management. Using a numeric scale to assess risks in relevance of importance also offers no absolute meaning (Ward, 1999).

If the scale goes from 1-25, is 25 relative to the end of the world where Bruce Willis needs to fly out to space to blow up an impending asteroid? Risks to crowd safety are complex and variable, and the understanding of variability should be the main focus of risk analysis. It’s the difference between the statistician crossing a river that is three feet deep on average and getting to the other side or not.

There is a wealth of knowledge and research conducted in the area of risk management, and varying formats of approaching risk analysis. According to Graham (2016) there is a family of risk that should be assessed, this includes;

– External risks
– Legal and regulatory risks
– Strategic risks
– Organisational risks
– Operational risks
– Information risks
– Human resources risks
– Technology risks
– Financial and administrative risks
– Political risks.

Identifying Risk

When it comes to crowd safety, we know it’s more than just the operational elements we interact with on the ground. We need to understand ever-changing components such as stakeholders, marketing, strategy, political environment, artist profile, ticketing, weather, technology, transport provision, catering plans and the audience profile; these factors all play a part in the safety of the crowd.

Research shows that there is rarely one reason but the interaction of minor failings that cause crowd disasters. For example, several factors contributed to the Love Parade disaster in 2010. However, all of the information required to mitigate the risks at this event were present. Had this information been risk assessed using tools appropriate for crowd safety, the disaster may have been averted. The data was there; it just needed to be worked on with the right tools and presented in a way we could ‘see’ the risk.

Applying Risk Theory

Chapman et al (2003) believe that ‘risk’ encourages an idea of threat and propose instead, the estimation and evaluation of ‘uncertainty’, providing a broader perspective accounting for variables such as stakeholder relationships.

Ward (1999) highlights the importance of risks typically rest on factors other than probability and impact and recommends using an alphabetic scale to highlight the subjective nature, removing the temptation to employ quantified ratings in ranking calculations.

Graham (2012) categorises risks into a four-square table of high/low risk v high/low frequency. Using Klein (2017) Recognition Primed Decision Making Model (RPDM), Graham focuses mitigating efforts on ‘High Risk/Low Frequency’ events as they historically have the highest likelihood of the worst consequences. This is due to little or no prior experience or knowledge of how to deal with a situation quickly if it were to arise.

First pass risk analysis models specifically designed for crowd safety include, among others, Fruin (2002) Force Information Space Time (FIST) and Still (2014) Design Information Management – Ingress Circulation Egress (DIM-ICE) and Routes Area Movement Profile Analysis (RAMP). They consider both mathematics and psychology; space the crowd occupies, how they interact with that space, their behaviour, and how we manage them. Tools such as software simulations can take a deeper focus on risks assessed via first-pass analysis and provide further data on crowd movement.


Above are some approaches in risk assessment that can be employed for crowd safety. They outline the wealth of research into improving risk management, taking into account the variable elements that surround the complex nature of crowds.

Considering the options available to us and the challenges we face in effective risk assessments, do we still see the PIG appropriate in effective risk management in crowd safety? Can we understand there are other tools in the toolbox?

There are more efficient approaches to better reduce the risk to people, property and reputation and enhance the safe delivery and positive experience to our crowd.

One thing we know for sure is that we need to make the risk assessment process as uncomplicated as crossing the road and getting to the other side, safely.

Special thanks to Ise Murphy.