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Three Insightful Methods for Causal Analysis

In this post, we will look at Three Insightful Methods for Causal Analysis.  Only three?!  If you search online, you will probably find eight methods coming up:

  • Pareto Charts;
  • Failure Mode and Effect Analysis (FMEA);
  • Five Whys;
  • Ishikawa Fishbone Diagram;
  • Fault Tree Analysis;
  • 8D Report Template Checklist;
  • DMAIC Template; and
  • Scatter Diagrams.

However, not all these methods are created equal!  Only some provide real insight to the challenge of causal analysis.  So, I’ve picked the best ones – based on my 25 years’ experience in system safety – and put them in this post.

What are Causes and Why are They Important?

Before we go any further, I just want to explain some basic terms.  When we’re doing safety analysis we have hazards and as the sort of bow tie diagram suggests, one hazard can have many causes and one hazard can have many consequences.

The Accident Sequence Illustrated.

Now, some of those consequences will be harmless but some may result in harm to people. And that progression from causes to hazards to consequences is known as an accident sequence. We tend to Okay? So we’re looking at the worst-case scenario where somebody gets hurt.

(It’s not really the focus of this post, but the test for a hazard is it’s necessary for the accident. If there’s no hazard, there’s no accident. Once the hazard is present, nothing else weird or unusual needs to happen. For the accident to occur. So, the hazard is both necessary and sufficient.)

I’ve mentioned consequences, but today we’re talking about causes. So, we will analyze the left-hand side of the bow tie.

Three Insightful Causal Analysis Methods

Pareto Analysis

So, let’s start with a Pareto Analysis. I suspect most of us have seen this before. If we look at the causes of a certain outcome. What we often find is that a few causes are dominant.

An Example of a Pareto Chart.

In this chart, we’ve got types of medication errors.  In this case ‘a dose missed,’ ‘wrong time,’ ‘wrong drug,’ and then ‘overdose’ accounts for 70% of the causation.  Everything else is only 30%.

(Now, here they drew a line at 80% as the cutoff because sometimes Pareto is known as the eighty-twenty rule. And that’s suggesting that maybe 80% of the outcome is caused by 20 percent of the inputs or causes.  In other words, most of the output variable is driven by only 20% of the input variables.  That’s just a rule of thumb, and it doesn’t have to be 80/20, it might be 70/30, or 60/40, it doesn’t matter.)

The point is there are some dominant causes. If we can identify the dominant causes, and we work hard on just those top 2, 3, 4, or 5 causes, then we can get a disproportionate reduction in risk by concentrating on those few things.  Whereas, we could spend an awful lot of effort at attacking all the other causes and make very little difference.

It’s a simple technique, but by being led by the data we can become far more effective at risk management.

Failure Mode and Effect Analysis (FMEA)

FMEA is covered in another webinar. 

Ishikawa Diagrams

So an Ishikawa diagram or a fishbone diagram, as it’s often called for obvious reasons. Is a causal diagram (Image By FabianLange at de.wikipedia), and it’s often used.

Example of an Ishiawa, or Fishbone, Diagram Structured for Causal Analysis.

In accident investigations, the Ishikawa diagram becomes a vital tool. I recall learning its application through the tragic case of the Piper Alpha oil rig disaster. Despite the grim nature of such events, they demand thorough causal analysis. Whether we opt for predefined groupings like equipment, process, people, materials, environment, and management, or let the data guide us, the essence remains unchanged: we investigate accidents to identify potential outcomes or problems and determine their contributing factors.

What makes this method invaluable is its ability to transcend technical issues alone. By encouraging us to consider the broader socio-technical environment, it prompts a holistic view of complex systems. The diagram visually represents primary causes directly linked to the main ‘fishbone’ of analysis, while secondary causes may contribute to or stem from these primary factors. The potential for tertiary causes exists in theory, but it may complicate matters without appropriate tools.

Utilizing this technique for brainstorming is highly effective. Displaying it on a whiteboard and collectively contemplating it as a group fosters focused discussions. Subsequently, formal documentation in various formats ensures thorough record-keeping. This method proves particularly powerful for unraveling complexities within systems, a topic worthy of a dedicated webinar.

Fault Tree Analysis

Fault Tree Analysis is another widely used technique. We’ll have a webinar devoted to FTA later.

The Eight Disciplines Method

The Eight Disciplines method is one of those I often get mixed up with something else. It was introduced by the Ford Motor Co. (I’ve never used it) but it looks like a sensible method. There are actually nine steps:

  • Prepare and Plan
  • Form your Team
  • Identify the Problem
  • Develop an Interim Containment Plan
  • Verify Root Causes & Escape Points
  • Choose Permanent Corrective Actions
  • Implement Corrective Actions
  • Take Preventative Measures
  • Celebrate with Your Team!

Effective problem-solving requires careful planning, especially when it’s a team effort. Let’s break it down into three key steps:

  1. Immediate Action: Start by addressing the urgency. What can we do right now to contain the problem while we develop a more comprehensive solution? It’s crucial to manage the issue in the short term as we work on a more refined approach.
  2. Identify Root Causes: Investigate when and how the situation spiraled out of control. Pinpoint the opportunities for errors within the process. Understanding the root causes and timing issues is essential before moving forward.
  3. Implement Permanent Solutions: Now that we’ve dissected the problem, it’s time to implement long-term corrective actions. This involves establishing better control measures and preventive strategies to avoid similar issues in the future.

Finally, it’s important to celebrate with your team once the solution is in place. Whether it’s going out for a meal or another form of recognition, acknowledging the effort is crucial.

This structured approach acknowledges the multi-stage nature of problem-solving. It emphasizes the need for short-term fixes, data-driven decision-making for long-term solutions, and proactive measures to prevent recurrences. Even if you take away nothing else, remembering these key points can guide you through the process. For more detailed information, check out the provided link, and stay tuned for a downloadable PDF with additional resources.

Bonus – Cause Analysis Reports

And a little bonus here, something I picked up while looking through this stuff if you go to smartsheet.com, you’ll find a whole bunch of nice templates on course analysis reports. Okay? So I haven’t been through them all but there looks like quite a lot of good stuff in there if you’re interested.

We’ve created root cause analysis templates you can use to complete your own investigations. Whether you need root cause analysis Excel templates, a root cause analysis template for Word, or a PDF template, we have one that’s right for your organization.”

https://www.smartsheet.com/free-root-cause-analysis-templates-complete-collection

More Resources

Interested in accessing more content from the Safety Artisan? Head over to my Thinkific platform, where you’ll find my courses and all the webinars available at the academy. Plus, you can test it out with a 7-day free membership trial. For those looking for an extended trial, use the code ‘one-month-free‘ to enjoy a full month on us. I am continually updating our content, adding new material every month to keep things fresh.

Additionally, sign up for free email updates to stay informed about upcoming webinars and other exciting events.

Meet the Author

Learn safety engineering with me, an industry professional with 25 years of experience, I have:

•Worked on aircraft, ships, submarines, ATMS, trains, and software;

•Tiny programs to some of the biggest (Eurofighter, Future Submarine);

•In the UK and Australia, on US and European programs;

•Taught safety to hundreds of people in the classroom, and thousands online;

•Presented on safety topics at several international conferences.

Categories
Blog System Safety

Understanding System Safety Engineering: A Quick Guide

Understanding System Safety Engineering: A Quick Guide, takes you through some key points of this complex subject.

Introduction

System safety engineering plays a crucial role in ensuring the safety of complex systems. In this post, we will explore the fundamental concepts of system safety engineering and its importance in the realm of systems engineering.

System Safety Engineering Explained

System safety engineering, as the name implies, focuses on engineering safety within a systems-engineering context. It involves deliberately integrating safety measures into the framework of complex systems.

Read on, or watch this short video for some pointers:

What is System Safety Engineering?

Key Points of System Safety Engineering

1. Consider the Whole System

In system safety engineering, a holistic approach is essential. It’s not just about hardware and technical aspects; it includes software, operating environments, functions, user interactions, and data. This comprehensive view aligns with systems theory, ensuring a thorough safety assessment.

2. A Systematic Process

System safety engineering follows a systematic process. Starting with high-level requirements, it meticulously analyzes potential risks, safety obligations, and components. The V model illustrates this structured approach, emphasizing the importance of verification and validation at every stage.

The #Systems-Engineering 'V' Model
The Systems Engineering ‘V’ Model

3. Emphasis on Requirements

Unlike simple commodities like toasters, complex systems require rigorous requirement analysis. System engineers meticulously decompose the system, defining boundaries, interactions, and functionalities. These requirements undergo rigorous validation, minimizing surprises and ensuring safety from the start.

Bowtie diagram showing five types of hazard analysis.
Bowtie showing the Foundations of System Safety

4. Think Safety from the Start

A significant aspect of system safety engineering is the early integration of safety considerations. By addressing safety concerns right from the beginning, potential issues are identified and resolved cost-effectively. This proactive approach enhances the overall safety of the system.

Setting the direction towards safety from the start
Which way should we go?

Summary

In summary, system safety engineering is characterized by its systematic approach to understanding the entire system, following a structured process, and integrating concepts from systems engineering and systems theory. By focusing on comprehensive requirements and thinking about safety from the start, system safety engineering ensures the safety and reliability of complex systems.

Meet the Author

My name’s Simon Di Nucci. I’m a practicing system safety engineer, and I have been, for the last 25 years; I’ve worked in all kinds of domains, aircraft, ships, submarines, sensors, and command and control systems, and some work on rail air traffic management systems, and lots of software safety. So, I’ve done a lot of different things!

Meet the Author

If you found this helpful, there’s more depth in this article, and you can also see System Safety FAQ. There’s a low-price introductory course on the System Safety Process – on Udemy (please use this link, otherwise Udemy takes two-thirds of the revenue).