Remember to mention any of the widely accepted methodologies for root cause analysis within your response. While an interviewer may be able to follow your description of a custom method, interviewers value candidates that have solid working knowledge of industry accepted methods.

"I have used a variety of root cause analysis methods in the past. They each have their place, and I customize the approach to fit the situation. Most commonly, I use the 5 whys method. It is easy to follow, and all of the members of my team can apply it.

In my current role in construction project management, we noticed that our projects were consistently experiencing delays in the steel erection process. I pulled together several of our senior leaders and field managers and facilitated a 5 Whys exercise. I started by describing the problem and then asking the group why it occurred. They indicated that the vendor we were using to hang steel was making a lot of mistakes. I then asked them why again. From there they let me know that the subs involved were unclear on the details of the plan and were using incorrect materials in many cases. I kept asking why until we got down to what we felt was the root cause.

It turned out that the guy responsible for project takeoffs at our steel vendor was new and wasn't creating detailed enough specifications. I contacted them and let their leaders know about the issues. They worked with the resources on their side to mentor the new resource and ensure that the plan quality we needed was in place for our next job. The delays were reduced as a result."