July 13, 2022 | Barb Carr

3 Reasons Why Your Investigation Results Are Only as Good as the Evidence You Collect

evidence collection

Incident investigators use all kinds of root cause methods to find and fix problems including brainstorming, fishbone diagrams, and 5-Whys. One of the problems with these types of methods is they don’t encourage good evidence collection. The evidence you collect is the foundation of your investigation, and preparation (collecting evidence) is key to performing a solid root cause analysis.

1. The evidence you collect keeps you out of your assumptions.

Last week, I posted, “Is This a Fact or Assumption-based Investigation?” The article highlighted that there are times we can see something with our own eyes but still be misled if we don’t do our due diligence in collecting evidence. Brainstorming, fishbone diagrams, and 5-Whys rely more on the knowledge and assumptions of the person or people conducting the investigation than information collection. As one course attendee told me, “prior to learning TapRooT®, we used brainstorming and the best assumption won most likely root cause!”

In my former life as a paralegal, I was trained by the attorneys to never include an assumption in any type of court document I drafted for them. Judges don’t like opinions, they just want the facts and respected the attorneys who focused on them. When you stick to the undeniable facts, it shifts the blame focus away from the people involved and shines it on the problems that occurred. Strive to collect at least two pieces of information to “prove” anything critical in the investigation.

evidence you collect

2. The evidence you collect will help you identify ALL the problems and root causes.

Another problem with brainstorming, fishbone diagrams, and 5-Whys is it encourages investigators to find the “rootiest root cause” and not all the problems. We hear the phrase “rootiest root cause” or some variation of this phrase all the time. It means that one root cause is the problem, and if it is fixed, the problems go away. It may seem that some mistakes were more hazardous and others less so but if you understand precursor incidents, you know that small problems can lead to major incidents. Take the time to collect information to understand everything that went wrong so that you can find and fix all the problems the first time.

Evidence collection is the most time-intensive step of any investigation. We estimate that a good 70% of your time will be devoted to it in a solid investigation. However, if you take a shortcut to root cause analysis and don’t spend the time collecting information, you will probably find yourself with a greater incident investigation workload. In the long run, it doesn’t save time and puts your workers and equipment at risk for another incident. The effectiveness of your safety program

3. The evidence you collect will help you get the resources you need to fix problems at your facility.

We’ve all been in situations where we’ve needed money or people resources to fix problems, and without management’s support, it’s hard to get buy-in. Investigators who perform evidence-based investigations earn respect from management. Why? Repeat incidents stop happening when you identify and fix all (and the right) root causes. It makes management look good. Management feels confident in the investigation when the evidence proves it.

Sometimes the root causes point to a failure in the management system (weak policies, lack of enforcement, poor communication), and management may feel singled out or blamed. Taking the time to document the investigation with evidence to make the facts irrefutable is important to getting root causes in the management system fixed.

TapRooT® Root Cause Analysis is an evidence-based investigation system.

Brainstorming, fishbone diagrams, and 5-Whys go straight to the question, “Why did this happen?” The TapRooT® System starts with “What do we know and what can we find out about what happened?” TapRooT® Investigators start with a SnapCharT® (a timeline and central repository of information collection), identify all of the mistakes made and equipment failures that occurred, and then analyze those in the TapRooT® Root Cause Tree®.

TapRooT® Root Cause Analysis is a guided system with a strong human factors component built-in. Investigators do not have to have the experience or knowledge of a human factors expert, they just need to follow the system. It helps incident investigators ask the right questions and requires the investigation team to collect information to perform the analysis. This takes the investigators out of their assumptions and helps them to see the big picture.


You can learn how to do a TapRooT® Investigation in as little as two days, even if you have never investigated an incident in your life.

Learn about 2-Day TapRooT® Root Cause Analysis Training.

Register for 2-Day TapRooT® Root Cause Analysis Training.

Want to learn all of this virtually?

Register for 3-Day TapRooT® Root Cause Analysis Virtual training. It is the same course but broken up into shorter days because who wants to sit online for 8 hours? Nobody! (It is a very fun and interactive course even though it is online.)

Improve your RCA with better evidence collection.

If you are frustrated with corrective actions that are not working and a heavy incident investigation workload, consider improving your root cause analysis with better evidence collection. There is no substitute for conducting a thorough, effective incident investigation.

Interviewing & Evidence Collection, Investigations
Show Comments

Leave a Reply

Your email address will not be published. Required fields are marked *