TOP-SET Methodology Compared To Fishbone Diagrams


TOP-SET Methodology compared to Fishbone diagrams

In the field of incident investigation and root cause analysis, there are several methods and techniques available. One of the most well-known and widely used is the fishbone diagram, also known as the Ishikawa diagram or cause-and-effect diagram. At Kelvin TOP-SET, we often receive questions from individuals and organisations about how our methodology compares to other root cause analysis methods, such as the fishbone diagram. In this post, we’ll explore the differences between the two approaches and highlight the advantages of the TOP-SET methodology.

What is a Fishbone Diagram?

A fishbone diagram is a visual tool used for root cause analysis. It resembles the shape of a fish skeleton, with the ‘fish head’ representing the problem or effect being analysed, and the ‘bones’ representing potential causes. These causes are typically categorised into broader categories such as people, equipment, materials, environment, and methods. During the fishbone method of root cause analysis, team members brainstorm and list potential causes under each category, gradually working their way towards the root cause. The fishbone diagram provides a structured approach to identifying and organising potential causes, making it easy to visualise and understand the relationships between different contributory factors.

The Pitfalls of Fishbone Diagrams in Root Cause Analysis

While fishbone diagrams can be a helpful tool for organising and visualising potential causes, they do have some limitations and pitfalls when it comes to effective root cause analysis. Let’s consider an example of a workplace incident involving a worker who sustained an injury while operating a piece of machinery.

Using a fishbone diagram for root cause analysis, you might categorise potential causes under various categories such as equipment (e.g., faulty machine, lack of maintenance), personnel (e.g., inadequate training, fatigue), and environment (e.g., poor lighting, excessive noise). However, the fishbone method of root cause analysis is restrictive and so may fall short in identifying the true root cause. This is because it focuses on immediate or surface-level causes rather than delving deeper into the underlying systemic or organisational factors.

Another limitation of fishbone diagrams is that they can become overly complex and cluttered, making it difficult to clearly identify the most significant contributing factors and the relationship between them. Additionally, the categorisation of causes can sometimes be subjective, leading to differing interpretations and potential biases.

How Does the TOP-SET method of Incident Investigation & Root Cause Analysis Compare?

The TOP-SET incident investigation and root cause analysis methodology takes a more comprehensive and structured approach to the process of investigation. Our methodology would involve the following steps:


  1. The Incident Statement
    TOP-SET teaches users how to write an accurate incident statement. This ensures the investigation stays on track and that investigators start the process knowing what they are investigating.
  2. Planning
    Using the TOP-SET Indicators (Technology, Organisation, People, Similar events, Environment and Time) and the TOP-SET Indicator Card widens the net for better-quality data gathering. With improved-quality data, the investigation is more likely to delve deeper into the incident and get more accurate results. Using the TOP-SET Indicators encourages wholly divergent thinking for data collection prior to analysis, which is critical, and ensures high-quality data are the inputs for analysis, i.e. no stone is left unturned, helping to minimise cognitive bias.
  3. Investigating
    On TOP-SET courses, delegates are taught the importance of gathering all types of evidence, which feeds the TOP-SET Storyboard and Timeline.
  4. Analysis
    The TOP-SET method ensures that all immediate, underlying and root causes are captured. There are numerous advantages to this systematic TOP-SET approach to root cause analysis, including being able to check the logic of the analysis flowchart.
  5. Report and Make Recommendations
    We teach TOP-SET users to develop effective SMART Recommendations based on their findings.
  6. Take Action and Review
    To learn from an incident and prevent future recurrence (and to prevent similar incidents from occurring) corrective actions are taken and these are reviewed periodically to ensure success.

The key strengths of the TOP-SET methodology are that it is easy-to-use, logical and highly practical – it’s much more than root cause analysis; TOP-SET is a complete investigation system.

The TOP-SET methodology provides a more comprehensive, in-depth and precise analysis compared to the method of fishbone diagrams, allowing for the identification of root causes beyond just surface-level or immediate causes. By considering organisational factors and systemic issues, our approach can uncover underlying weaknesses that may have contributed to the incident, enabling more effective recommendations that really deal with the problem.

Additionally, our structured methodology ensures a consistent, objective and reliable approach to incident investigation, minimising the potential for biases or subjective interpretations to influence findings.

While fishbone diagrams can be a useful tool for organising and visualising potential causes, they may fall short in identifying the true root causes and underlying systemic factors that contribute to incidents. The TOP-SET methodology offers a more comprehensive and structured approach to learning from incidents, enabling a deeper understanding of the root causes and organisational factors involved. This methodology is central to all our incident investigation training courses, equipping participants with the skills and knowledge to effectively investigate incidents and implement corrective actions to prevent recurrences.

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