Six Sigma as a Framework to Improve Incident Investigation

Safety is an important manner in the workplace. Workplace incidents continue to occur in high frequencies. High numbers of fatalities significantly impact both people and the economy negatively, and to a great extent. Lean practices can streamline documentation, improve workplace conditions, enhance performance, and accelerate emergency response times — all of which is expected to improve safety performance. However, a systematic process for the elimination of errors is needed in order to maintain positive performance. Six Sigma fits this purpose well and can be used to eliminate safety errors in the workplace and maintain improved performance over time.

Six Sigma is an effective quality management system used to improve workplace performance including safety. One example of how the Six Sigma system can be used to improve workplace safety performance is through the incorporation of the Six Sigma DMAIC framework in incident investigations. DMAIC (which stands for Define, Measure, Analyze, Improve, and Control) is a structured methodology used to identify causes of defects and implement countermeasures to improve the quality of the process in terms of safety, productivity, and so forth. This blog briefly describes a Six Sigma DMAIC framework intended to investigate root causes of workplace accidents.

Define Phase

In this phase, the scope of the problem should be identified. The investigation team should determine the type of incident under investigation (e.g., near miss or fatal injury). Importantly, the roles and responsibilities of all parties involved in a project or a workplace should be clearly identified and fully understood by the investigation team so that a comprehensive investigation can be performed.

Measure Phase

The objective of this stage is to assess safety performance and collect relevant data that can be used to evaluate current and previous safety performance. When investigating an incident, the components of safety risk (frequency of exposure to hazard and severity of the hazard) should be determined. The magnitude of risk can be a useful indicator of safety performance. Conducting an employee survey and focus-group interview with workers, for example, are effective methods that the investigation team can implement to collect relevant data on employee awareness of workplace hazards, risks associated with the hazards, and employee compliance with safety requirements.

Analyze Phase

After obtaining the necessary data during the previous stage, the investigation team should analyze the data empirically and statistically to determine the root causes of incidents. There are many graphical tools that can be helpful during the analysis process especially in the case of investigating root causes of defects (safety defects in this case). These tools include Pareto charts, fishbone diagrams, quality control charts, and 5-whys technique.

Improve Phase

At this point, the root causes of incidents should be fully determined and completely comprehended. If this is not the case, then it can be concluded that the investigation process is somehow faulty and ineffective. In such cases, the investigation process should be fixed and repeated. On the other hand, if root causes of incidents are fully determined and completely comprehended, the investigation team, along with other critical project personnel (e.g., workers), should start identifying and implementing corrective and preventive countermeasures to improve workplace conditions. These countermeasures can take different forms both proactive and reactive, but the focus should be on implementing proactive measures that can eliminate exposure to workplace hazards, thus preventing workplace accidents. However, reactive actions, such as safety training, can also contribute positively to improving workplace safety conditions.

Control Phase

After identifying and implementing countermeasures, safety performance should be tracked and monitored to ensure that the intended results have been achieved. This phase of the proposed framework is critical because it can provide verification that root causes of incidents were correctly identified and successfully eliminated. In regard to safety, generally, achieving high levels of safety is not difficult to accomplish, but ensuring that high performance levels will be sustained over a long period of time is the challenge. A minor decision can sometimes have catastrophic impacts on safety performance and can lead to tragic incidents involving serious injuries or even fatalities.

The proposed Six Sigma framework can be combined with lean practices to reduce not only root causes of injuries but also waste and inefficiencies in the process.

This blog is based on an article that was published by the American Society of Safety Engineers’ (ASSE) Professional Safety Journal. The article can be accessed via the following link:

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