Friday, September 3, 2010


Risk is a tricky thing to pin down and, as with most things in hazards analysis, open to a wide range of interpretations. A useful website for discovering just how open to debate this term is is John Adams website ( We all encounter risk everyday. The financial markets have just collapsed under the weight of risks. We drive along the motorway aware of the risk of other drivers (at least I hope everyone else does as I do!). We weigh up the risk to our health, the length of our life, of another drink, another cigarette, another burger or pie. Or do we?

Risk can seem to be such an easy thing to define. You can work out the probability of something occurring- the probability of dying from smoking a specific number of cigarettes per day, the probability of a specific amount of alcohol per day giving you cancer, the probability of contracting cancer given a specific level of exposure to radiation. Trouble is people often act as if they don’t know these probabilities exist.

Risk can be defined accurately, mathematically and scientifically using statistical analysis. Risk can be defined as the chance of a particular defined hazard or event occurring. If you now the frequency of occurrence of a particular level of flow in a river then you can work out the probability in any one year that there will be a flow of a given magnitude. Leaving aside problems of how long does the record of flows need to be to be representative, how well are extreme events represented in that record and many other factors, the key point is that, in theory, risk can be calculated from such records. Risk can be given a number: a fixed value that informs people and what they should do. Btu why should risk bother you? Risk only becomes important because you feel you might have something to loss. Risk can only be defined in relation to loss, so only within a context of fear or loss. It can be refined as a simple equation of:

RISK = [Hazard (probability) x Loss (expected)]/ Preparedness (loss mitigation)

You can see how each bit of the equation could be given a number. The hazard from scientific analysis of the geophysical nature of the hazard or rather the probability of the hazardous event. Loss can be calculated by the amount of money you would need to replace what you could lose if the event happened. Preparedness, more tricky, but maybe how much you can pay to insure against you loss by that hazardous event. But is this all risk really is?

There are other ways of looking at risk.
  • Risk can be defined as being a real thing, out there and so subject to scientific and mathematical analysis and calculations that are common across experts.
  • Risk can be seen as a cultural and social phenomenon created by the society we live in and so subject to change as that society changes
  • Risk can be defined legally as a responsibility or a failure of expected conduct
  • Risk can be defined psychologically as a set of behaviours and understandings about the world
  • Risk can be defined within the humanities as an emotional phenomena and as a story or narrative

    Each of these different definitions illuminates different aspects of risk and may ring true with individuals in different circumstances. When watching news reports about floods in Pakistan, for example, I am seeing risk as a story or narrative dictated by the media and its beliefs about how I expect the disaster to unfold. Never underestimate the tight constraints of such storylines in affecting how we see things. Risk of injury on a building site could be viewed through the lens of legal definitions of risk and responsbility. The reactions of individuals to flooding and flood risk could be viewed through the lens of psychology. Some people believe in the risk and insure, others don’t and save their money – are the first group risk averse, the second risk takers or is it more complicated than that?

    There is another way of defining risk, either singularly or in combination.

    • Real: the calculation approach as above plus objective below
    • Objective: the risk is real, a thing and it is out there for us to study and quantify
    • Observed: Risk we can measure given our particular view of the world (and given it is real and objective)
    • Subjective: Risk is about mental states of individuals who are only human and so plagued by fear, worry, uncertainty and doubt
    • Perceived: subjective estimate of risk by individual or group

    I would argue that all risk is perceived and that risk tends to be defined by the judgements of people, singularly and in groups, based on their application of some knowledge or information about the uncertainty involved, where this knowledge or information is objective, observed or subjective. When we believe or precieve the risk to be generated by some real, physical phenomenon then we can meausre it and calculate risk. This does not mean others will share our view of the world as objective nor our view of risk as soemthing objective.

    What this means is that the perception and belief of risk varies from individual to individual, from group to group, from place to place and even from event to event. Trying to model or generalize about the actions of individuals in the face of risk is difficult but in future blogs I hope to present some models and general ideas about how people have tackled this complicated problem of understanding how people perceive and react to risk.

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