To What Extent Do Accidents at Work Result from System Errors?

The statement that all accidents at work are caused by errors in operator-machine systems (system errors) presents a deterministic view of workplace safety. While system errors undoubtedly contribute to accidents, it is an oversimplification to completely disregard other factors, particularly human error. This essay will argue that accidents often stem from a complex interplay of both human and system shortcomings, drawing on research to illustrate the multifaceted nature of this issue.

Human Error as a Contributing Factor

Human error, encompassing a range of cognitive and behavioural lapses, plays a significant role in workplace accidents. Riggio (1990) provides a useful framework for understanding these errors, categorising them as omissions, commissions, sequence errors, and timing errors. This highlights the diverse ways in which human actions, or lack thereof, can compromise safety.

Furthermore, individual factors can increase the likelihood of errors. Tiredness and fatigue, for instance, impair alertness and decision-making, while alcohol and drug use can have even more severe effects on cognitive function and motor skills. Additionally, certain personality traits, such as impulsivity and risk-taking, have been linked to a higher incidence of accidents, suggesting the influence of accident-prone personalities (e.g., as discussed in the work of Guastello, 1993).

The work environment itself can also exacerbate human error. Studies have consistently shown a higher frequency of errors during the "graveyard" shift (8pm-6am), likely due to the human biological clock being ill-suited to this time period. This underscores the importance of considering circadian rhythms and providing appropriate support for night shift workers.

Finally, in high-pressure situations, humans are prone to errors in judgement and action. The use of motion stereotypes, or relying on ingrained responses even when inappropriate, highlights how stress can override rational decision-making in emergencies.

The Role of System Errors

While human fallibility is undeniable, system errors contribute significantly to workplace accidents. Poorly designed systems can create conditions ripe for human error, essentially setting workers up for failure. The Three Mile Island incident serves as a chilling example of how a confluence of system errors, including poor interface design and inadequate training, can lead to catastrophic consequences.

Even at a smaller scale, design flaws in machinery can have serious repercussions. Inadequate lighting can obscure hazards, quiet buzzers may fail to alert workers to dangers, and user-unfriendly controls can lead to confusion and incorrect operation. All these factors highlight the crucial role of ergonomic design and user-centered engineering in promoting workplace safety.

The Interplay of Human and System Errors

In reality, most accidents are not solely attributable to either human or system errors. Instead, they often arise from a complex interaction between the two. A poorly designed machine may be more prone to misuse, but human complacency or inattention can exacerbate the risk. Conversely, even a well-designed system can be compromised by inadequate training or poor communication.

This understanding is reflected in the concept of the "operator-machine system," which emphasizes the interdependence of human and technological components. An effective approach to accident prevention must therefore address both sides of this equation, focusing on both reducing human error and designing more robust and user-friendly systems.

Conclusion

In conclusion, attributing all accidents solely to system errors presents an incomplete picture of workplace safety. While human error is an undeniable factor, system design plays a crucial role in either mitigating or amplifying these errors. Research consistently demonstrates that the most effective approach to accident prevention involves a multifaceted strategy that addresses both human and system factors, fostering a safety culture where both elements work in harmony.