Introduction to risk modelling and decision analysis (course in Univ Kuopio)

This page contains the open material for the course Introduction to risk modelling and decision analysis, a course held in the University of Kuopio, 18.-22.9.2006.

Schedule of the course

Mon 18 September, 2006 Medistudia, Room MHS1

• 9:15-10:00 Introduction to course and distribution of homework Jouni
• 10:15-11:00 Perspective on risk (definition of risk measures, system boundaries) pp. 1-24, oma riskimääritelmä Jouni
• 11:15-12:00 History of risk research (Red book approach, Nuclear safety) Olli

Tue 19 September, 2006 Medistudia, Room MHS1

• 9:15-10:00 Risk management pp. 147-189 Jouni
• 10:15-11:00 Exposure assessment pp. 68-80 Olli
• 11:15-12:00 Dose-response assessment, Risk assessment tools (NOAEL, benchmark, CSF, RfD) pp. 46-68, animal-human extrapolation Olli

Wed 20 September, 2006 Medistudia, Room MR10

• 9:15-10:00 Probability theory [frequentist and subjective (Bayesian) approach] Marja-Leenalla sopivia kirjoja? Uncertainty 220-230. Jouni
• 10:15-11:00 Monte Carlo simulation and other tools (uncertainty pp. 81-98) Analytica Olli
• 11:15-12:00 Decision theory (utility, decision tree, utilitarian, egalitarian and other decision rules) [1]

Markolla Introduction to decision theory? Jouni

Thu 21 September, 2006 Medistudia, Room MHS1

• 9:15-10:00 Graphical representations of risk (DAG, impact pathway, event tree, mind map, pyrkilo, flow chart) Mikan Intarese-paperi, Analytica, pp. 38-46, D1 Beneris Jouni
• 10:15-11:00 Perception of risks (trust, attributes of risk, expert vs. layman perception) pp. 99-134 Olli
• 11:15-12:00 Models in risk assessment (pharmacokinetic Jouni, atmospheric) pp. 68-75, Portierin luennot http://ytoswww/yhteiset/Huippuyksikko/Kirjallisuus/Portier_AdvMetERA_20051011/, Johnin luennot Harvard, Kopran esittely (Marko)

Fri 22 September, 2006 Canthia, Room MC3

• 9:15-12:00 Computer work in a computer classroom. Finishing and presenting homework. Using Wiki and Pyrkilo.

Homework

Look at the new page about the risk assessment

Task:

• To create, define, and describe variables related to Hämeenkyrö case (both general and case-specific)
• To make them match with the other variables (dimensions, units, interpretation)
• To defend the choices in an open argumentation and summarise the resolutions
• To comment and argue the choices of other students

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Perspectives on risk

Definitions of risk and related issues

1. Hazard, endanger, exposure to mischange or peril. (Oxford English Dictionary)
2. The chance of hazard or commercial loss. (Oxford English Dictionary)
3. As in Risk-Money, an allowance paid to a cashier to cover accidental deficits. (Oxford English Dictionary)
4. Risk = Probability ⊗ Severity (Wilson and Crouch)
5. Risk = S{Probability ⊗ Severity ⊗ Weight} (Wilson and Crouch)

   ⇤However, sometimes risks are not truly multiplicative.: (Tversky et al., 1990) {{{3}}}

6. Risk: a characteristic of a situation or action wherein two or more outcomes are possible, the particular outcome that will occur is unknown, and at least one of the possibilities is undesired. (Covello and Merkhofer, 1993)
7. Risk is such a property of a situation that tells that it is uncertain which of the possible outcomes will occur, at least one of them is unfavourable, and that there is a need to improve the expectation of the outcome. (Tuomisto, 2006)

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Development of risk management

Table I. Developmental Stages in Risk Management (Ontogeny Recapitulates Phylogeny)

1. All we have to do is get the numbers right
2. All we have to do is tell them the numbers
3. All we have to do is explain what we mean by the numbers
4. All we have to do is show them that they’ve accepted similar risks
5. All we have to do is show them that it’s a good deal for them
6. All we have to do is treat them nice
7. All we have to do is make them partners
8. All of the above
   

(Fischhoff, Risk Analysis 1995:15:137)

What is risk assessment?

Traditional view

A scientific enterprize consisting of four phases:

• Hazard identification
• Exposure assessment
• Dose-response assessment
• Risk characterization

⇤But these phases do not capture the issues raised by Fischhoff. Therefore, something better should developed.: Jouni {{{3}}}

Suggestion for a new view on risk assessment

Risk assessment research should answer the following two questions:

• What are the rules that enable an open (non-organised, non-fixed) group of rational actors to describe environmental health risks and resolve disputes that arise during the process about the content?
• When should I, as a rational critic who judges reasonably, regard a risk assessment as acceptable? (modified from van Eemeren and Grootendorst, 2004)

Measures of risk

Possible outcome measures (indicators)

• Deaths...
  • by age
  • by cause
• Injuries...
  • by cause
  • by type
  • by some sort of severity index
• ...per
  • year
  • lifetime
  • unit operation
  • event
  • ton
  • unit output

• Loss of life expectancy
• Working days lost
• Public days lost
• Quality adjusted life years (QALY)
• Disability adjusted life years (DALY)

• Ecological and other indicators

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Defining system boudaries is a critical thing.

The probability of causation (POC)

POC = P(risk from the cause of interest)/P(risk due to all causes)

What is the POC for PM_2.5 causing cardiovasular deaths in the EU?

What is the POC for vinylchloride causing angiosarcoma in liver?

Graphical representations of risk

• Directed acyclic graphs (DAG)
• impact pathway
• event tree
• mind map
• pyrkilo
• flow chart