I think that risk includes two components: the probability of a hazard occurring in a specific place at a specific time with specific characteristics + the damages that it may cause which is named vulnerability.

Therefore, in my opinion, it has to do with the territory (or environment) but also with populations (not only to humans). As Collins et al. (2009) says: “even a high magnitude hazard event poses no risk when it occurs in the absence of a vulnerable population. Conversely, a vulnerable population experiences no risk if there is not a probability of a hazard event occurring in their presence”.

Nevertheless, a definition for the term “risk” depends on which field you are working (landslides, forest fires, volcanic eruptions, technological hazards….).

Dear Gema Herrero Corral. There is no general and universal concept of risk, like for example a concept of gravity (this thing that makes bodies fall against earth's surface, or that gives them weight when on earth's surface, not gravity in the sense of importance, seriousness). Saying that "risk is the probability of a hazard occurring in a specific place at a specific time with specific characteristics + the damages that it may cause which is named vulnerability" one is simply a process of pilling up words which meanings are taken for granted, words that are not previously specified in terms of meaning. In my opinion, a definition for the term “risk” depending on which field we are working (landslides, forest fires, volcanic eruptions, technological hazards….) is the same as saying that a definition of "gravity" depends the same way on which field we are working (landslides, forest fires, volcanic eruptions, technological hazards….). Landslides, for example, are linked to gravity, but this gravity is the same that acts on a stone falling down from a plane flying, on a football player falling back after jumping etc. All these situations do not demand different concepts of gravity (the one which provokes the acceleration measured by the constant g = 9,8.... m/s*s). I continue my journey. That now is not a lonely one anymore.

Dear Adriana, I know Knight's book. Frank Knight was not concerned about language. Calling events with "known probability" risks, and events of unknown probability "uncertainties", is no less arbitrary as Ulrich Beck's use, misuse and abuse of the word "risk" (See Elliott's article "Beck’s sociology of risk: a critical assessment" in Sociology 2002; 36(2): 293-315 (. Please refer also to Chapter VI of Mises' book "Human Action". When referring to risk people use a possible "operational definition" of risk as concept of risk.

Dear Adriana, see also:

Campbell S, Currie G. Against Beck: in defence of risk analysis. Philosophy of the Social Sciences 2006; 36(2): 149-72.

Risk is the variation of variables that we study which it was not as expected.

I like the concept of risk as the set of all possible accident scenarios, their frequencies (probabilities) and consequences (damage states).

In occupational health practice, risk is defined simply the likelihood of an injury or disease when exposed to a hazardous situation. But cultural and social understanding of risk posed a big problem when requesting for information on the risk inherent in the activities of workers. In theory occupational health and safety resources should be devoted to reducing risks in workplaces. This principle may seem to be the correct one to those concerned with the problem of identifying and characterizing health and safety risks. However, certain social and cultural issues are contrary to this principle. Firstly, it is apparent from many studies that peoples’ perspectives of risk do not match those of experts . For instance, in Nigeria society where there is mass unemployment working in hazardous environment or handling hazardous chemical is not regarded as a risk in most cases. This is more so when the consequence of the exposure to health hazards in particular is insidious in nature. The situation becomes more complex to comprehend because ill health incurred from these exposures will not manifest until serious damage might have been done. In most cases the affected persons become patients in tertiary hospitals where often clinical interventions could not restore the damages to the organs affected. Also self-imposed risk is well tolerated than the risk imposed by others in Nigeria. This was discovered to be a common perception among self-employed such as workers in small scale enterprises (SSEs). The economic barriers are also substantial. For instance, many SSEs on the edge of survival cannot afford any additions to their operating costs even though they may promise significant savings in the future. Thus, they may not be able to afford education and training in risk reduction.

Dear Andre, Sir, your definition of "Risk" doesn't convey anything but would thoroughly confuse a Newbee. Had you given the same definition to a word called "Tisk" or "Bisk", It would not have meant anything different. Before trying to defy the agreed concept of the word "Risk" which has been clearly and consistently quantified in the literature please understand a concept put forth by Lord Kelvin quoted below

Quote -"When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be" - Unquote. Please quantify the statement if you can for clarity.

Dear Valiveti, my account is hard to follow when people keep having the egg-shells from the old view sticking to their thoughts (See Wittgenstein, Culture and Value, 44).

Measuring is not knowing. Concept has nothing to do with measure. People measured mass long before scientific reasoning about a concept of mass. The retailer that measures the mass of commodities he's selling does not worry about a concept of mass (if asked, he will say that he measures the weight of commodities; sometimes the retailer even dos not know the word "mass"). So the same with risk management experts. For practical purpose, it does not matter what concept of risk one has in mind. Maybe the quest for a concept of risk is MY problem, not a scientific need.

Risk is the probability of an adverse outcome. The nature of the outcome will be dependent upon the particular discipline or setting. For example, there is a financial risk with investing revenue in a start-up company - one may lose their investment. There is a risk of obtaining a disease if one comes in contact with an infectious individual. There is a risk of property damage if homes are constructed near earthquake faults. There is a cancer risk that can be quantified (as a probability) should an individual come into contact with environmental media contaminted with a carcinogenic chemical (i.e., environmental exposure).

Dear Robin Rodriguez, if you understand probability as possibility (without quantification), then it is a good attempt to develop a concept of risk.

A definition of risk is not complete if it does not take into account 'consequence'. The probability of losing the money invested in a start-up company is high. The probability of losing the money is exactly the same whether you invest a large sum of money or a small sum. The RISK is reduced by investing only a small sum, because if you lose it the consequences will not be so severe. A simple definition of risk is 'potential for loss.'

Risk is harm from a hazard. Risk assessment is the activity that aims to quantify the likelihood, probability, and distribution amongst the population of that harm.

Andrew Peck pointed to a very good concept of risk. Charles Haas gave a good idea concerning distintion between a concept of risk and the activity of risk assessment.

Risk is perception of fear of something wrong. It is is deviations of the actual return from targeted return. It is fear of not meeting the target. In case of investment the risk assessment is the first step for the risk management. It includes the sources of risk and to evaluate their impact on the possible outcome. It also include the deviation from the desired result. Open for further comments.................

Mr. Joseph Mullat, your comment enriches the quest for a concept of risk, as you call attention to a very important point. In fact, speaking about risk we must take into account the difference between probability as a measure and possibility as something possible, even when not a desirable outcome. I hope you will agree.

Risk is the probility of a hazard resulting in an adverse event and it's severity.

In addition to Hamid's nice definition: it should be emphasised that 'exposure' to the hazard is of paramount importnat; for health risk, one could define it mathematically as equation Risk as a function of Hazard and Dose (in which Dose is the exposure in time): Risk = f(Hazard, Dose).

If there is no or nigligible exposure, there is no risk.

Risk could be thought of as combination of the probability of occurrence of harm and the severity of that harm. In this context, harm could be defined as physical injury or damage to the health of people, or damage to property or the environment and hazard could be the potential source of harm.

Francis Bacon: "Truth will sooner come out of error than from confusion."

The confusion I refer to is that some answers give the name "risk" to some OPERATIONAL DEFINITIONS, i.e., "measurement of something", but do not touch the core of the question, a CONCEPT of risk. Let me explain what I mean. For centuries traders measured the weight or the mass of goods (depending on what they used, a balance or some device ressembling a dynamometer) without any reference to a concept of mass or of weight. (Reminder: The difference between mass and weight was grasped by the French scientist Jean Richer in 1671, the first person to discover that gravity varied over the Earth's surface). I insist that measurement of something and a concept about it are different matters.

Well, this question opens up a potential can of worms (meaning that many potential answers exist, and some people hold dearly their preferred definition).

I would say that there are two major ways to look at risk. The first is a more quantitative/objectivist view. The second is more qualitative/interpretivist in nature.

The first group pretty consistently defines risk as the probability of a negative event multiplied by the consequences. Probability is threat (intent and/or capability to adversely affect a system) multiplied by vulnerability (capability of being harmed). Consequence is understood to be damage minus resilience (the ability to recover the system within a reasonable time and at an acceptable cost).

The second group is less unified on a common definition. I prefer the conceptualization that considers risk to be the socially constructed perception of the likelihood of a negative event and its possible consequences. I also advocate risk as a function of probability, consequence, control, and dread. Control is a composite of the extent to which the risk is voluntary, "regulate-able", etc. Dread is a composite of how scary the threat is, how foreign or strange the risk is, the extent to which the risk is equitable, etc.

So ultimately, you have a shot at a common formula with the first group (although risk will never be measurable in the same way that gravity is). But the second group would be fundamentally opposed to treating risk like gravity. To them, risk is not an objective phenomenon.

Hope that helps!

What you refer to in your 'second group' is commonly known as "risk perception". Dependent on many factors (experience, social status, knowledge, level of control etc.) people will perceive the same risk totally different.

Peter - Yes, that's right. Although "risk perception" also describes the area of study concerned with how people's understanding of risk is attenuated or amplified by the factors you noted.

If the way people understand risk varies based on socio-cultural factors, then there can not be an operationalization of risk in the same way we define gravity.

Dear Steven Venette, dear Peter Boogaard: I liked your comments. Very helpful for my project on philosophy of risk. Thank you!

Risk is uncertainty which causes the adverse impact on the revenue inflow of any concern. It is further about the perception of the individual how he treat the risk. It can be an opportunity for those who treat it as opportunity.

It might be useful to differentiate between different types of risk, at least on how they are perceived. You might be killed as a result of an earthquake and it depends in which part of the world you live whether the risk is high or low. If you've experienced an earthquake at some stage in your life, you probably perceive a much larger risk than when you've never been in one, despite the actually calculated, statistical risk. With health risks due to chemical exposure it is also very much a matter of perception. For instance, most people don't realise that more than half of all cancer is caused by living (i.e. breathing, eating, drinking). In fact, life can be considered a sexually transmitted terminal disease. The big runner up is smoking, which kills more people than any other single cause. Chemicals in the environment, whcih many people think are the cause of disease, actually form only a very minor cause. In the total scheme of things, obesity, alcohol (ab)use, stress etc. are far more important quantitatively. This, of course, does not take away to control chemical exposure (not at all: anything reasonably preventable should be prevented !), but a etter perception on actual risks might give a better perspective on what individuals might be able to do themselves to control risks. Very similar as controlling the risks such as taken in other areas of life, e.g. dangerous sports (may be very healthy, but might bring a risk), risks people take in traffic etc.

Dear friends, Congratulation for the ongoing discussions. Let me give two definitions of risk (in the context of safety or loss control). First one is what you all are taking, i.e., risk is a measure of hazard potential. Although there are variants, the most popular one is 'risk is the probability of the occurrence of an undesired event times its consequence (impact or severity, etc.)'. It is used to prioritize hazards for control actions. In this context, the definition of hazard is "something which has potential to cause harm to human, damage to equipment or environment". Therefore, from industrial or occupational safety point of view, risk has no value unless the corresponding hazards for which risk is computed is known.

The second definition is 'entropy'. All of us know that entropy is the distortion or decaying of a system (or its components). From design for safety point of view, entropy is a better measure of risk. No matter how best a system is designed, there will be design flaws introducing some amount of risk, known as residual risk. On the passage of time, the system elements (process, technology, procedures, human) deteriorate (e.g., wear and tear) causing more distortion or decaying than the designed one. If unnoticed, the deterioration (entropy) reaches to the threshold value sufficient to cause an incident (or accident). This, therefore, necessitates the use of maintenance, monitoring and control of health of the system elements. The entropy risk of the process and technology can be controlled through engineering approaches to safety, and that of the procedures and human can be controlled through organizational and behavioral approaches to safety. In summary, every system possesses two types of risk, the residual (inherited) and the entropy risk.

I agree with definitions mentioned by Mr. Muraleedharan Vayalappil and Steven Venette. I teach the students in Faculty of Occupational Safety, University of Nis, Serbia that measure of risk (R) is probability of hazard(s) (G), multiplied with a cost of possible consequences,(C).

Of course risk has to do with probability. It is a probability, i.e. the likelihood of an adverse outcome. Thus, in environmental parlance, risk is a function of hazard (e.g. toxicity) and exposure (e.g. magnitude and duration of contact with the hazard).

Dear Daniel, I am after a concept of risk, not after a measure of something.

Dear Daniel, a comparison. What is gravity? Newton himself said that he was unable to explain the nature of gravity. But gravity provokes acceleration. In spite of not knowing gravity's nature, we indeed measure an effect of it.

Indeed, risk is the likelihood of an adverse outcome. For example, cancer risk is the likelihood that a given exposure to a carcinogen (hazard) will lead to the adverse outcome of the disease. This can be at the individual level, e.g. lifetime exposure to this agent or, more commonly, at a population level (e.g. lifetime average daily dose [LADD] for a given population. You used the analogy to gravity, which is a physical concept. Risk is a statistical concept. Gravity can be measured and controlled in empirical ways, however, risk's components can be measured (estimated) and controlled to varying degrees (e.g. hazard is often extrapolated from animal studies - dose-response, but with intraspecies, interspecies and other uncertainties; LADD is extrapolated from observational studies that vary in similarity to the population for which you are predicting risks.

I suggest you become familiar with Hill's criteria for causality, a benchmark to distinguish association (empirical observations and weight of evidence) with causality in medical research. Epidemiologists have grappled with risk assessment for decades. They are not trying to find the "risk particle," but want to know which physical, chemical and biological first principles explain their observations in populations. We are nowhere near physicists' conception of gravity, but we are getting better at predicting when the apple will fall and where it might land.

I have read all of this discussion from the perspective of 'enlightenment-seeker'. The enlightenment I'm seeking is how or what method/process is used in the decision-making as too what to include and what to exclude? For example; crossing a road. There are some very simple obvious steps such as looking and listening before deciding to cross. But then it can become far more obtruce; if a car is indicating to turn left at a left hand turn and we are passed the left hand turn and there are no other vehicles, is it safe to cross? Same scenario but now include weather conditions of heavy rain and mist, is it still say to cross? How about amending this still further to dry road, clear sky low setting sun into visibility of the driver, is it still safe to cross. Even more specific, at still the same crossing point in clear weather and high sun with temperature exceeding 30 degrees C and heat haze present on road, or vehicle behind it noticed some way back, is it still safe to cross?

The risks and hazard potentials soon quickly mount up yet this is a very simple everyday activity when compared and contrasted with others.

The precautions I guess then must be what soon mounts up, as presented in the above case. Factors such as, speed (pedestrian, vehicles), weather conditions (sun, rain, snow, ice, wind, heat), environment (wet leaf litter on road) road layout (width of road, pot-holes to avoid, junctions, mid road waiting place, traffic lights) and so the lists goes on of what needs to be factored in and the relevant precautions put in place for.

Perhaps, we in the environmental risk arena approach this less philosophically and more probabilistically than some other fields. We consider a number of factors, indeed we call them risk factors, that increase the likelihood of an adverse event, i.e. increase the risk. For example, a mean lifetime risk of lung cancer can be calculated for an entire population. However, this must be stratified and confounders must be controlled for this to be an accurate reflection of risk from a particular agent or activity. A person exposed to asbestos will have a higher risk with greater exposure, i.e. a dose-response or biological gradient (one of Hill's criteria for causality). If that person also smokes tobacco, the risk is increased substantially. This is usually done for entire populations or subpopulations, rather than for an individual. A subpopulation is stratified for important risk factors (e.g. gender, age, smoking and genetic susceptibility. One population may have orders of magnitude greater additive risk than another due to these risk factors.

Risk has a strong temporal element as I'm confident we can all agree. My experience of risk assessment and management has been extremely political. The case in point is:

A council officer sets such high conditions in place in order to negate risk for school children in physical activity to the nth degree. The short term result is no child will probably get hurt whilst attending a council-run or sponsored service locally as the precautions in place are that draconian. for the council officer the result is the least number of injured children whilst they hold that office, compared with other officers and their predecessors. This leads to the least number of litigation cases involving injured children during his office, leading to good pr and increasing their chance of either staying in their office when other officers are being laid off, or the officer being promoted. Results for the children though are - increased injury rates out of council controlled areas as they have not learnt to experience or manage risk themselves as these opportunities were removed from them to reduce the probability of them being injured. Higher degree of risk aversion behaviours due to poor perceptions of risks at the other end of the scale. In the long term over their life time the probability is that they will die younger and suffer more long term chronic medical conditions, due to their lack of exposure to physical activity in the school years this officer was in post. A reason - evidence is reasonably strong linking the exposure and uptake to physical activities in the school years that is inspiring and motivational to children increases the probability of them maintaining it into adulthood and through much of their lives.

Yet because of the extreme short-term approach to risk assessment I has seen and heard justified in the above case, practiced for personal/professional/political reasons; these very same children who the officer maintains are under their duty of care are likely to experience higher injury rates or be more risk averse than their peers, as well as likely comparatively be able to live less productive lives as a result of the above factors.

I have to admit that I have not yet come across 'a life-time' risk assessment tool that factors in the likely probability of the short term actions. Thus reducing the chances of the above occurring dramatically. Has anyone else?

Tee - Thank you for that explanation. I have been struggling with a major risk assessment for more than a year now, as I have been put off not knowing where to start. I don't know if you or any others with knowledge and experience of risk assessment would be willing to advise through this medium? It relates to a research problem I am about to undertake in the field of mountaineering with the aid of siberian huskies and people who are experiencing poverty and deprivation. It is to measure health and poverty changes probably due to the experience of the expedition. My struggle is how I go about undertaking a formal risk assessment of this situation. My background is public health and I mountaineer and work with Siberian Huskies for fun, so undertake my own personal dynamic risk assessment all of the time; so many of the key variables are not constant but fluid and the systems are also in a state of flux. How is all of this formally captured and recorded?

Risk refers to the reduction or loss of income due to undesirable events and unfavorable conditions for uncertain and changeable economic entities.

Again, defining risk is highly contextual. For example, in our paper, Communicating Risk and Resiliency: Special Considerations for Rare Events, J.D. Solomon and I noted that the International Organization for Standardization (ISO) defined risk as the effect of uncertainty on objectives and that such effect can be either positive or negative (ISO 31000: 2009 Risk management–Principles and guidelines International Organization for Standardization, Geneva, Switzerland. 2009). Quoting from our paper:

A competing risk framework by the Council of Supporting Agencies (COSA) adopts a similar core definition but state that “risks” are negative effects and “opportunities” are positive effects. To many laypeople, who would probably agree with the latter interpretation, this does not seem like a big deal; however, the ISO 31000 definition dominates among the technical risk management and infrastructure project management communities. The ability to communicate effectively can be hampered from the outset primarily because technical professionals often cannot communicate what risk means in terms that laypeople understand and also because they may not share a common definition among themselves.

The definition of risk is further complicated by the number of ways it can be expressed. In the engineering community, risk is most frequently expressed by what is commonly known as the risk equation, which is the multiplicative product of the consequences of failure and the likelihood of failure. Within the public health and security community, risk is often understood to be synonymous with vulnerability, which is expressed as the multiplicative product of the consequences of failure, the hazard rate, and the likelihood of experiencing the hazard. In this sense, risk is indirectly proportional to reliability. Technical professionals often say that either of these methods define “risk.” Rather, these and many other methods are simply ways to express risk. Risk is the effect of uncertainty on objectives, and to most laypeople that means the negative effect (loss). Indeed, environmental and public health agencies define risk as a probability of an adverse outcome (e.g. mortality, morbidity, loss of habitat, and diminished ecological diversity). Environmental risk is often expressed as quotient of hazard and exposure (Vallero, D. Environmental Biotechnology: A Biosystems Approach: Elsevier Science. 2015).