Risk, Errors & Accidents
- Created by: Sess
- Created on: 18-05-15 06:34
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- Risks, Errors & Accidents
- Risks
- Acceptance of Risk
- Consequences
- If the consequences are long term, we accept the risk
- e.g. Smoking
- If the consequences are long term, we accept the risk
- Controlability
- If its out of our control, we accept risk
- e.g. The risk of pollution from air
- If its out of our control, we accept risk
- Knowledge
- If we know little about the situation
- e.g. Nuclear power plant
- If we know little about the situation
- Consequences
- Risk Homeostasis & Target Risk
- Everyone has an internal acceptable level of risk
- If something is easy, greater risk is accepted. If it is hard, less risk is accepted
- Wilde (1982)
- An equilibrium of perceived risk needs to be maintained
- Shared Space
- Monderman (1991)
- Removed traffic lights, road separators
- People perceived more risk so they drove more carefully
- Risk Compensation
- The adjustment of people's behaviour in response to perceived level of risk
- Seatbelts
- Janssen (1994)
- Compared data from people who habitually wore or didnt wear seat belts
- Those that wore seat belts tended to drive more recklessly, maintaining level of casualties between the two
- Such theories have been criticised, saying there is little evidence to support
- Ruedl et al (2010)
- Definition
- The probability (perceived likelihood of an event/condition
- Violation in the Workplace
- Looked at violation in the workplace of offshore oil rig workers
- Patrick Hudson (1998)
- Found 4 types of people that responded to risk
- Wolves in sheeps clothing are most dangerous as we do not know when they will violate next
- People take risks because..
- They feel powerful enough
- There arnt enough rules
- There are opportunities for shortcuts
- Rules must be bent for work to be done
- Acceptance of Risk
- Accidents
- Characteristics
- Low expectancy to occur
- Low chance of avoidance
- Unintended
- Something is damaged
- Personal Blame
- Accidents are the result of the inadequacy of humans that attempt to adjust to a particular set of circumstances
- Ardous & Kerrick (1951)
- Accident Proness
- Some people are more accident prone than others
- The young and inexperienced or the old and slow etc
- Sequential Theories
- Domino Theory
- Heinrich (1932)
- All factors are dependent on the preceding factor
- Injury occurs due to accidents, which occur due to mechanical or personal hazards which occur due to careless persons or faulty equipement
- Human Factors Theory
- Accidents occur after a chain of events set off by human error
- Human error occurs due to overload, inappropriate activities, inappropriate responses
- Domino Theory
- Multi-factorial Theory
- Reese (1990)
- The 'Swiss Cheese' Model
- This model assumes that there are always hazards waiting to become accidents
- We should design systems with multiple layers to prevent them from occuring
- However, if there is a clear accident trajectory through the layers, an accident will occur
- Definition
- The unplanned outcome of inappropriate behaviour or faulty machinery
- Brown (1976)
- Characteristics
- Errors
- Types
- Omission
- Leaving out a step or a whole task
- Comission
- Sequence
- Tasks are done in the wrong order
- Timing
- A task is executed before or after it is required
- Selection
- Using the wrong controls
- Quantity
- An inadequate amount or excess of something
- Sequence
- Swain & Guttman (1983)
- Omission
- Dealing with them
- Selection
- Reducing errors by selecting the right sort of people for the job
- Training
- Altering their risk perception
- Reinforcing good behaviour
- Design
- Making it as fail safe as possible
- But all errors cannot be accounted for
- Selection
- Human reliability is studied
- Technique for human error-rate prediction involves identifying human errors
- Once errors are identified, possible changes to the system are made
- Types
- Risks
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