We want to assure the quality of our designs. We want to prove to ourselves and to our business leaders that we are appropriately addressing risk, but we don’t want to waste time or turn risk management into a overburdening task.
Our process improvement and risk management tools are nothing more than a means of organizing and communicating information. There are many tools to choose from and each serves a purpose. Sometimes we have more than one tool for the same purpose and we develop our preferences depending upon our critical concerns.
What we don’t always consider is that using two tools can be faster than using one. It is true when we achieve a synergy between the two tools. My favorite combination of risk management and quality assurance tools is a synergy of Fault Tree Analysis and Failure Modes and Effects Analysis (FMEA). Let me explain why.
The FMEA has been the go-to tool for risk analysis and failure prevention since the 1940s. It is an excellent tool because its proper use drives us to identify potential failure modes and root causes, predict the effects of failures, assess the severity of such outcomes, predict the probability of the occurrences and prioritize how we will address each. It is a very thorough process and tool.
The down side of “thorough” is that it is necessarily time consuming. When the FMEA matrix begins to exceed 100 lines of potential failures, it’s no longer a practical exercise, it’s drudgery and the effectiveness of the tool as a tracking and communication instrument begins to break down. When the possible failures stretch to 400 line items, it can take a month just to fill out the matrix.
As a result, many engineering teams that I have encountered prefer a Fault Tree Analysis, or one of many similar tools to predict and proactively address risk. There are hundreds of practical and useful ways to deploy a fault tree, beginning at a high level and running over the whole system, or doing a miniature tree for each component. It can be relatively quick and efficient, especially if the design is already mapped in a component tree or function diagram format.
The limit to the fault tree tools is that they don’t plainly identify and track the most important potential failures, the plans to mitigate or prevent them, or the progress toward the completion of those plans. It is typically quicker to perform than FMEA, but it lacks the depth of information.
So, many years ago, some of my engineering partners and I developed a way to have our “quick and dirty,” and our assurance of quality too. We began using them both. On top of that, we achieved better information and tracking instead of having to compromise. Synergy.