environmental

4 Characteristics of an Effective Root Cause Statement

Three people talking on the shop floor in an industrial environment

The hardest part of any continuous improvement process is accurately identifying the reason that risk is present in the system to begin with. This is also the most critical step when implementing improvements. There are four key characteristics that every root cause statement should include to provide quality data that can result in effective solutions.

#1: Describes the reason for the action or outcome, not the action itself

The goal of any root cause is to understand the reasons why risk factors occur in a job following a baseline musculoskeletal disorder (MSD) risk assessment. The risk assessment should have already identified the risk factors, and probably includes some form of media to reference, such as a picture or video, so that it’s not necessary to put the task into words. A root cause statement should take it one step further and explain why the task is causing the risk exposure. One way to drill down to this underlying cause is called the “5 Whys.” To use this method, imagine you’re describing the task to a child who keeps asking you “why?” You’ll know “why” when you have arrived at an explanation that is simple and fixable.

#2: Clearly links to the problem(s) or risk factor(s) that were previously identified

Every root cause analysis should begin with the risk factor exposure. Every high-risk assessment score should be related to a root cause. This is also an opportunity to perform a validity check on your risk assessment. If you can identify a problem within a job that does not clearly link to a risk factor from your evaluation, then perhaps you made a mistake. For example, a root cause of “force too high” would not make sense if your risk assessment doesn’t show a force threshold met for any body segment.

#3: Includes values for the current state, when appropriate

Root cause statements are used to generate improvement ideas. Therefore, if a force is too high or a distance is too far, the improvement must focus on changing that measurement. But, if the current state is unknown, how will you know if your modification made it any better? Also, if your company submits changes to equipment or layout to a maintenance team for execution, you’ll need to tell them exactly how much to change the dimension. For example, rather than telling maintenance to “lower a shelf using design guidelines for ergonomics,” the request can be to “lower the shelf 3" to meet design guidelines.”

#4: Is the natural inverse of the solution

This check is a verification of both the root cause statement and the improvement recommendation. The identification of improvements should always begin with the list of root causes and brainstorming countermeasures. The link between the improvement and the root cause should be obvious. For instance, with a root cause of “the vertical reach to the top storage shelf is too high at 63" from the floor,” the improvement should focus on lowering the height of the items being stored. There may be more than one way to reduce the height, such as no longer using the top shelf of a rack or simply lowering the height of the shelf, but the objective will be to reduce the height of the vertical reach.

Read, "How to Use Design Guidelines to Create a Successful Ergonomics Process."