## Accidents, Safety, and Risk: Study Notes ### How Common Are Accidents? Heinrich's Law (Heinrich, 1931) suggests a consistent ratio of 1:29:300 for fatal/major injuries, minor injuries, and near misses in industrial accidents. This "accident triangle" highlights the potential for predicting and preventing major incidents by analyzing less severe ones. Heinrich's work emphasizes the importance of proactive safety measures, focusing on preventing even minor incidents. A common misconception is that Heinrich's ratio is universally applicable and unchanging. Research suggests it's difficult to replicate consistently. However, critics (Anderson & Denkl, 2010) point out the difficulty in replicating Heinrich's ratio and the overemphasis on individual worker responsibility, neglecting systemic factors like management policies. Furthermore, reducing minor incidents doesn't guarantee a reduction in major ones. ### Why Don’t People Follow Safety Instructions? Zeitlin (1994) identifies two potential breakdowns: **information transfer** (failure to effectively communicate the hazard) and **compliance** (knowing the safeguards but choosing to ignore them). Understanding the reasons behind non-compliance is crucial for designing effective safety interventions. Reasons for disregarding safety information include: * **Perceived low probability of risk:** Expected utility theory suggests people weigh the likelihood and severity of consequences. * **Perceived control:** People accept more risk when they feel in control. * **Cost-benefit trade-off:** Weighing the inconvenience of safety measures against potential consequences. * **Culture:** Societal norms and attitudes influence risk perception. * **Sensation-seeking personality:** Zuckerman (1994) highlights the role of personality traits in risk-taking behavior. A study comparing experienced and novice chainsaw users showed that experience influenced compliance with safety instructions, suggesting that perceived necessity plays a role. ### How Can Accidents Be Reduced? Wogalter (1994) outlines four key strategies: 1. **Hazard removal:** Eliminating the source of danger. 2. **Guarding:** Protecting against hazards that can't be removed. 3. **Training:** Educating individuals on safe practices. 4. **Warnings:** Providing clear and effective warnings about residual risks. Effective warnings should include: * A strong signal word (e.g., "DANGER"). * A clear hazard description (e.g., "high voltage lines"). * A description of the potential consequences (e.g., "electrocution risk"). * A clear instruction (e.g., "Do not touch"). The effectiveness of warnings is influenced by factors such as attention, beliefs, motivation, and behavior. Sanders & McCormick (1993) suggest improving safety-compliant behavior through: * **Proceduralization:** Establishing clear procedures. * **Training:** Focusing on safe behaviors and ensuring transfer to the task. * **Feedback:** Providing regular feedback on performance. * **Reinforcement:** Using positive reinforcement strategies and incentive programs. * **Increased awareness:** Raising awareness of risks. ### What is Probable Risk Analysis? Probable risk analysis (or assessment) estimates the consequences of errors by multiplying the probability of an error by the severity of its consequences: $Risk = p(error) \times Consequences(error)$. This method helps prioritize risk mitigation efforts by focusing on high-impact scenarios. This analysis is used in various decision-making processes, including safety estimations and resource allocation. High-probability/low-consequence risks are often underestimated. ### How Does Target Risk Explain Risky Behavior? Risk Homeostasis Theory (Wilde, 1994, 2001, 2014) proposes that individuals maintain a target level of risk. If safety measures reduce objective risk, individuals may compensate by engaging in riskier behaviors to restore their preferred level. This theory suggests that simply making things safer doesn't always lead to a reduction in accidents. This target risk is influenced by: 1. Expected benefits of risky behavior. 2. Expected costs of risky behavior. 3. Expected benefits of safe behavior. 4. Expected costs of safe behavior. The introduction of child-proof medicine bottles led to an increase in childhood poisonings, as caregivers became less vigilant. The Peltzman effect (1975) supports this, showing that safety improvements in cars led to increased risky driving behaviors, offsetting some of the safety benefits. ### What is Shared Space, and How Does It Reduce the Risk of Collisions? Shared space (Monderman, 2005) is a counterintuitive approach to urban design that integrates vehicle and pedestrian traffic without traditional traffic control devices (signs, signals, markings). The ambiguity forces drivers to slow down and pay more attention, creating a safer environment despite the apparent lack of safety measures. The key is to create an environment where drivers feel a greater sense of responsibility and caution. Studies in Drachten, Netherlands; Christianfield, Denmark; and other locations show significant reductions in collisions and increased pedestrian and cyclist traffic in shared space areas. Evidence suggests that shared space can lead to: * Improved traffic flow. * Reduced collisions (especially serious ones). * Enhanced aesthetics. * Less "nannying" (reduced reliance on rules and regulations). However, potential drawbacks include: * Lack of clear information for drivers, especially those with disabilities. * Potential for conflicts between different user groups. * The effect may be temporary, as drivers may become less cautious over time. ### The Premortem Strategy The Premortem Strategy (Klein, 1998; 2007) is a proactive risk analysis technique used before implementing a plan. It involves imagining a future where the plan has failed and identifying the reasons for that failure. This technique leverages prospective hindsight and mental contrasting to identify potential problems before they occur. The steps involved are: 1. **Know the plan:** Familiarize the team with the plan. 2. **Imagine a failure:** The team imagines the plan has failed and writes a brief history of the disaster. 3. **Generate reasons for failure:** Each member identifies reasons for the failure. 4. **Consolidate the lists:** Reasons are compiled and discussed. 5. **Revisit the plan:** Address the most concerning issues and strengthen the plan. 6. **Periodically review the list:** Monitor for emerging problems. Evidence suggests the premortem strategy reduces overconfidence and improves the effectiveness of planning.