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Risk assessment is the determination of quantitative or qualitative value of risk related to a concrete situation and a recognized threat (also called hazard). Quantitative risk assessment requires calculations of two components of risk (R):, the magnitude of the potential loss (L), and the probability (p) that the loss will occur. Acceptable risk is a risk that is understood and tolerated usually because the cost or difficulty of implementing an effective countermeasure for the associated vulnerability exceeds the expectation of loss.
In all types of engineering of complex systems sophisticated risk assessments are often made within Safety engineering and Reliability engineering when it concerns threats to life, environment or machine functioning. The nuclear, aerospace, oil, rail and military industries have a long history of dealing with risk assessment. Also, medical, hospital, social service and food industries control risks and perform risk assessments on a continual basis. Methods for assessment of risk may differ between industries and whether it pertains to general financial decisions or environmental, ecological, or public health risk assessment.
- 1 Explanation
- 2 In public health
- 3 In auditing
- 4 Human health
- 5 In information security
- 6 In project management
- 7 For megaprojects
- 8 Quantitative risk assessment
- 9 In software evolution
- 10 Criticisms of quantitative risk assessment
- 11 In shipping industry
- 12 See also
- 13 References
- 14 External links
Risk assessment consists of an objective evaluation of risk in which assumptions and uncertainties are clearly considered and presented. Part of the difficulty in risk management is that measurement of both of the quantities in which risk assessment is concerned – potential loss and probability of occurrence – can be very difficult to measure. The chance of error in measuring these two concepts is high. Risk with a large potential loss and a low probability of occurrence, is often treated differently from one with a low potential loss and a high likelihood of occurrence. In theory, both are of near equal priority, but in practice it can be very difficult to manage when faced with the scarcity of resources, especially time, in which to conduct the risk management process. Expressed mathematically,
Financial decisions, such as insurance, express loss in terms of dollar amounts. When risk assessment is used for public health or environmental decisions, loss can be quantified in a common metric such as a country's currency or some numerical measure of a location's quality of life. For public health and environmental decisions, loss is simply a verbal description of the outcome, such as increased cancer incidence or incidence of birth defects. In that case, the "risk" is expressed as
If the risk estimate takes into account information on the number of individuals exposed, it is termed a "population risk" and is in units of expected increased cases per a time period. If the risk estimate does not take into account the number of individuals exposed, it is termed an "individual risk" and is in units of incidence rate per a time period. Population risks are of more use for cost/benefit analysis; individual risks are of more use for evaluating whether risks to individuals are "acceptable".
In public health
In the context of public health, risk assessment is the process of quantifying the probability of a harmful effect to individuals or populations from certain human activities. In most countries the use of specific chemicals or the operations of specific facilities (e.g. power plants, manufacturing plants) is not allowed unless it can be shown that they do not increase the risk of death or illness above a specific threshold. For example, the American Food and Drug Administration (FDA) regulates food safety through risk assessment. The FDA required in 1973 that cancer-causing compounds must not be present in meat at concentrations that would cause a cancer risk greater than 1 in a million over a lifetime. The US Environmental Protection Agency provides basic information about environmental risk assessments for the public via its risk assessment portal. The Stockholm Convention on persistent organic pollutants (POPs) supports a qualitative risk framework for public health protection from chemicals that display environmental and biological persistence, bioaccumulation, toxicity (PBT) and long range transport; most global chemicals that meet this criteria have been previously assessed quantitatively by national and international health agencies.
How risk is determined
In the estimation of risks, three or more steps are involved that require the inputs of different disciplines:
- Hazard Identification, aims to determine the qualitative nature of the potential adverse consequences of the contaminant (chemical, radiation, noise, etc.) and the strength of the evidence it can have that effect. This is done, for chemical hazards, by drawing from the results of the sciences of toxicology and epidemiology. For other kinds of hazard, engineering or other disciplines are involved.
- Dose-Response Analysis, is determining the relationship between dose and the probability or the incidence of effect (dose-response assessment). The complexity of this step in many contexts derives mainly from the need to extrapolate results from experimental animals (e.g. mouse, rat) to humans, and/or from high to lower doses. In addition, the differences between individuals due to genetics or other factors mean that the hazard may be higher for particular groups, called susceptible populations. An alternative to dose-response estimation is to determine a concentration unlikely to yield observable effects, that is, a no effect concentration. In developing such a dose, to account for the largely unknown effects of animal to human extrapolations, increased variability in humans, or missing data, a prudent approach is often adopted by including safety factors in the estimate of the "safe" dose, typically a factor of 10 for each unknown step.
- Exposure Quantification, aims to determine the amount of a contaminant (dose) that individuals and populations will receive. This is done by examining the results of the discipline of exposure assessment. As different location, lifestyles and other factors likely influence the amount of contaminant that is received, a range or distribution of possible values is generated in this step. Particular care is taken to determine the exposure of the susceptible population(s).
Finally, the results of the three steps above are then combined to produce an estimate of risk. Because of the different susceptibilities and exposures, this risk will vary within a population.
When risks apply mainly to small sub-populations, there is uncertainty at which point intervention is necessary. For example, there may be a risk that is very low for everyone, other than 0.1% of the population. It is necessary to determine whether this 0.1% is represented by:
- all infants younger than X days or
- recreational users of a particular product.
If the risk is higher for a particular sub-population because of abnormal exposure rather than susceptibility, strategies to further reduce the exposure of that subgroup are considered. If an identifiable sub-population is more susceptible due to inherent genetic or other factors, public policy choices must be made. The choices are:
- to set policies for protecting the general population that are protective of such groups, e.g. for children when data exists, the Clean Air Act for populations such as asthmatics or
- not to set policies, because the group is too small, or the costs too high.
Acceptable risk criteria
The idea of not increasing lifetime risk by more than one in a million has become commonplace in public health discourse and policy. It is a heuristic measure. It provides a numerical basis for establishing a negligible increase in risk.
Environmental decision making allows some discretion for deeming individual risks potentially "acceptable" if less than one in ten thousand chance of increased lifetime risk. Low risk criteria such as these provide some protection for a case where individuals may be exposed to multiple chemicals e.g. pollutants, food additives or other chemicals.
In practice, a true zero-risk is possible only with the suppression of the risk-causing activity.
Stringent requirements of 1 in a million may not be technologically feasible or may be so prohibitively expensive as to render the risk-causing activity unsustainable, resulting in the optimal degree of intervention being a balance between risks vs. benefit. For example, emissions from hospital incinerators result in a certain number of deaths per year. However, this risk must be balanced against the alternatives. There are public health risks, as well as economic costs, associated with all options. The risk associated with no incineration is potential spread of infectious diseases, or even no hospitals. Further investigation identifies options such as separating noninfectious from infectious wastes, or air pollution controls on a medical incinerator.
Intelligent thought about a reasonably full set of options is essential. Thus, it is not unusual for there to be an iterative process between analysis, consideration of options, and follow up analysis.
For audits performed by an outside audit firm, risk assessment is a very crucial stage before accepting an audit engagement. According to ISA315 Understanding the Entity and its Environment and Assessing the Risks of Material Misstatement, "the auditor should perform risk assessment procedures to obtain an understanding of the entity and its environment, including its internal control."<evidence relating to the auditor’s risk assessment of a material misstatement in the client’s financial statements. Then, the auditor obtains initial evidence regarding the classes of transactions at the client and the operating effectiveness of the client’s internal controls.In auditing, audit risk is defined as the risk that the auditor will issue a clean unmodified opinion regarding the financial statements, when in fact the financial statements are materially misstated, and therefor do not qualify for a clean unmodified opinion. As a formula, audit risk is the product of two other risks: Risk of Material Misstatement and Detection risk. This formula can be further broken down as follows: inherent risk X control risk X detection risk.
There are many resources that provide health risk information.
- TOXNET (databases on hazardous chemicals, environmental health, and toxic releases),
- the Household Products Database (potential health effects of chemicals in over 10,000 common household products),
- TOXMAP (maps of the U.S. Environmental Protection Agency Superfund and Toxics Release Inventory data).
In information security
IT risk assessment can be performed by a qualitative or quantitative approach, following different methodologies.
In project management
In project management, risk assessment is an integral part of the risk management plan, studying the probability, the impact, and the effect of every known risk on the project, as well as the corrective action to take should that risk occur. Of special consideration in this area is the relevant codes of practice that are enforce in the specific jurisdiction. Understanding the regime of regulations that risk management must abide by is integral to formulating safe and compliant risk assessment practices.
Megaprojects (sometimes also called "major programs") are extremely large-scale investment projects, typically costing more than US$1 billion per project. Megaprojects include bridges, tunnels, highways, railways, airports, seaports, power plants, dams, wastewater projects, coastal flood protection, oil and natural gas extraction projects, public buildings, information technology systems, aerospace projects, and defence systems. Megaprojects have been shown to be particularly risky in terms of finance, safety, and social and environmental impacts.
Quantitative risk assessment
Quantitative risk assessments include a calculation of the single loss expectancy (SLE) of an asset. The single loss expectancy can be defined as the loss of value to asset based on a single security incident. The team then calculates the Annualized Rate of Occurrence (ARO) of the threat to the asset. The ARO is an estimate based on the data of how often a threat would be successful in exploiting a vulnerability. From this information, the Annualized Loss Expectancy (ALE) can be calculated. The annualized loss expectancy is a calculation of the single loss expectancy multiplied by the annual rate of occurrence, or how much an organization could estimate to lose from an asset based on the risks, threats, and vulnerabilities. It then becomes possible from a financial perspective to justify expenditures to implement countermeasures to protect the asset.
In software evolution
Studies have shown that early parts of the system development cycle such as requirements and design specifications are especially prone to error. This effect is particularly notorious in projects involving multiple stakeholders with different points of view. Evolutionary software processes offer an iterative approach to requirement engineering to alleviate the problems of uncertainty, ambiguity and inconsistency inherent in software developments.
Criticisms of quantitative risk assessment
Barry Commoner, Brian Wynne and other critics have expressed concerns that risk assessment tends to be overly quantitative and reductive. For example, they argue that risk assessments ignore qualitative differences among risks. Some charge that assessments may drop out important non-quantifiable or inaccessible information, such as variations among the classes of people exposed to hazards. Furthermore, Commoner and O'Brien claim that quantitative approaches divert attention from precautionary or preventative measures. Others, like Nassim Nicholas Taleb consider risk managers little more than "blind users" of statistical tools and methods.
In shipping industry
In July 2010, shipping companies agreed to use standardized procedures in order to assess risk in key shipboard operations. These procedures were implemented as part of the amended ISM code.
- Acceptable loss
- Benefit risk
- Control self-assessment
- Cost risk
- Digital Continuity
- Edwards v. National Coal Board
- Extreme risk
- Flood risk assessment
- Form 696
- Green Globe
- HACCP: hazard analysis and critical control points, risk assessement in food
- Hazard (risk)
- Hazard Identification
- Health Impact Assessment
- Information assurance
- List of auditing topics
- ISO 28000
- ISO 31000
- Megaprojects and Risk
- Network Theory in Risk Assessment
- Optimism bias
- PIMEX a video exposure monitoring method
- Probabilistic risk assessment
- Probit model
- Reference class forecasting
- Risk aversion
- Risk management
- Risk management tools
- Risk Matrix
- Risk (statistics)
- Security risk
- Strategic misrepresentation
- Risk based auditing
- RFC 4949
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- Merrill, Richard A. "Food Safety Regulation: Reforming the Delaney Clause" in Annual Review of Public Health, 1997, 18:313-40. This source includes a useful historical survey of prior food safety regulation.
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- "Risk Assessment and Regulation Information from the NLM". NLM. Retrieved 9 June 2013.
- "Databases on toxicology, hazardous chemicals, environmental health, and toxic releases". TOXNET. NLM. May 2012. Retrieved 9 June 2013.
- "Household Products Database". U.S. Dept. of Health & Human Services. January 2013. Retrieved 9 June 2013.
- "Risk Assessment Portal". EPA. 13 May 2013. Retrieved 9 June 2013.
- Managing Project Risks - Retrieved May 20th, 2010
- Commoner, Barry. O'Brien, Mary. Shrader-Frechette and Westra 1997.
- The fourth quadrant: a map of the limits of statistics [9.15.08] Nassim Nicholas Taleb An Edge Original Essay
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- Jean-Lou, C. M.; Dorne, George E. N. Kass, Luisa R. Bordajandi, Billy Amzal, Ulla Bertelsen, Anna F. Castoldi, Claudia Heppner, Mari Eskola, Stefan Fabiansson, Pietro Ferrari, Elena Scaravelli, Eugenia Dogliotti, Peter Fuerst, Alan R. Boobis and Philippe Verger (2011). "Chapter 2. Human Risk Assessment of Heavy Metals: Principles and Applications". In Astrid Sigel, Helmut Sigel, Roland K O Sigel. Metal Ions in Toxicology. RSC Publishing. pp. 27–60. doi:10.1039/9781849732116-00027.
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- Library of Congress. Congressional Research Service. & United States. Congress. House. Committee on Science and Technology. Subcommittee on Science, Research, and Technology (1983), A Review of risk assessment methodologies, Washington: U.S: report / prepared by the Congressional Research Service, Library of Congress for the Subcommittee on Science, Research, and Technology; transmitted to the Committee on Science and Technology, U.S. House of Representatives, Ninety-eighth Congress, first session
- Deborah G. Mayo. “Sociological versus metascientific views of technological risk assessment” in Shrader-Frechette and Westra.
- Nyholm, J, 2009 "Persistency, bioaccumulation and toxicity assessment of selected brominated flame retardants"
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