Righting the Wrongs
Why it’s important to find the root cause—and how to do it
by Les Schnoll
Regardless of the industry or quality system being followed, when things go wrong, an investigation is necessary. One of the deliverables of that investigation is the determination of the problem’s root cause. Unfortunately, most organizations do not have a clue when it comes to root cause determination, and their inability to meet the requirement can be disastrous from regulatory and business perspectives.
"The mechanics of running a business are really not very complicated when you get down to essentials," author John L. McCaffrey wrote. "You have to make some stuff and sell it to somebody for more than it cost you. That’s about all there is to it, except for a few million details."1
Fortunately, problem solving is a simple matter of answering a series of questions:
- What exactly is the problem?
- Who owns the problem?
- How bad is it?
- What is causing the problem?
- How can the cause be fixed?
- Did the fix work?
On the surface, it sounds pretty simple. Regrettably, most companies stop far short of answering all the questions. As long as the symptom is addressed, the organization does not follow through and determine the root cause.
How to proceed
An effective corrective and preventive action (CAPA) system requires a systematic approach, consistent structure and organized procedures, as well as common sense. Participants should avoid jumping to conclusions and remember to use their skills and experience to solve problems.
For the CAPA system to be effective, there must be a clear understanding of the difference between preventive actions used to address systemic conditions and corrective actions used to address nonsystemic or sporadic conditions.
Systemic conditions are long-standing adverse situations, the remedies of which require changing the status quo (preventive action). Sporadic conditions involve sudden adverse changes to the status quo and require restoring the status quo (corrective action). The difference between the two conditions means that quite different actions are required to remedy them.
A corrective action eliminates a nonsystemic root cause of nonconformances and establishes controls so the root cause cannot recur. It’s called a nonsystemic root cause because it is not part of the system design. Nonsystemic root causes are usually few in number, have a significant impact and are easy to identify.
Detecting a nonsystemic root cause is achieved by investigating the conditions surrounding a nonconformance and identifying what changes were made to the system. These root causes are usually associated with unexpected events or changes that are not part of the original system design.
Eliminating nonsystemic root causes requires restoring and maintaining the system. Often, additional system controls need to be established to detect and prevent the recurrence of these root causes. Effective corrective action increases the stability of a process. Fewer fluctuations and sudden shifts in system performance will occur as more nonsystemic root causes are removed.
Preventive actions detect and eliminate a systemic root cause of nonconformances and prevent future occurrences. Systemic root causes get their name because they are endemic to the system, numerous and taken for granted. Individually, the associated nonconformances tend to have small consequences. But collectively, those effects add up and make a significant impact on other areas related to the system.
Systemic root causes arise when there are numerous nonconformances of the same class or type. Root causes are detected through trend analysis or other special analyses that look for patterns of substandard performance or clusters of nonconformances.
Eliminating systemic root causes requires changing the system, which usually requires management authorization. Effective preventive action increases process capability. Detecting, eliminating and preventing systemic root causes reduces the long-term, inherent variation of a process.
There are many acceptable, proven methods that can be used in the CAPA process to identify and eliminate the root cause of the problem, including this eight-step system:
- Create a problem statement.
- Select the team.
- Contain the problem.
- Describe the problem.
- Determine the root cause.
- Verify the root cause.
- Implement action.
- Measure and monitor results.
But even if you follow a defined process, the root cause will never be identified unless proper tools are used. These tools may include statistical analyses, the five whys, brainstorming and fishbone (Ishikawa) diagrams. In my experience, one of the best tools to help identify the root cause is the is/is not matrix (see Table 1).
This tool identifies the facts of the problem, provides a summary of the facts to test possible causes, identifies missing information and establishes a clear boundary around the problem. Ultimately, this matrix describes what the problem is and what it is not, providing a description of what else you could or should be having problems with but are not.
The is/is not matrix requires input in the form of answers to questions under the general categories of what, where, when, how bad and trends. When properly completed, the team will be able to answer the question: "How could the potential cause explain the ‘is’ response and not the ‘is not’ response?"
After the chart is completed, the team members will have a good idea of where to focus. Then, they can test to determine whether the probable root cause really is the culprit.
The next critical step in the process to determine root cause is to verify that the probable cause is, in fact, the root cause. To accomplish this, the team looks at the possible causes and tests each of them against the data in the chart. If the possible cause is not eliminated, it is tested in the operation to verify it is the true root cause.
Root causes must be verified before any further action is taken. This can be accomplished via a three-step process:
- Narrow the list of all possible causes to a list of the most likely.
- Prioritize the shortened list with the most likely cause at the top.
- Devise a test to verify whether the most likely cause is the real root cause. If it is not, move on to the second most likely cause and devise a test for it.
Verify the cause of your problem by turning the problem on and off. If you can duplicate and eliminate the problem by changing your input, you have found your root cause.
The entire team should be involved in developing potential solutions and devising tests to verify solutions that are cost efficient, able to be implemented rapidly and unlikely to allow the problem to return. But make sure the fix is not the cause of a new problem for you or someone else.
Get on the train
Why do so many organizations fail to identify the root cause? The root cause of this inability to find the root cause is insufficient training.
There are myriad available programs that teach proper techniques and processes, and organizations should take advantage of them because of the importance of accurate, complete and timely investigations.
Failure to perform the process adequately puts an organization at risk—financially and, if in an industry regulated by the Food and Drug Administration, legally (see sidebar, "Letter of the Law").
Letter of the Law
"Each manufacturer shall establish and maintain procedures for implementing corrective and preventive action. The procedures shall include requirements for analyzing processes, work operations, concessions, quality audit reports, quality records, service records, complaints, returned product, and other sources of quality data to identify existing and potential causes of nonconforming product or other quality problems. Appropriate statistical methodology shall be employed where necessary to detect recurring quality problems; investigating the cause of nonconformities relating to product, processes and the quality system; identifying the action(s) needed to correct and prevent recurrence of nonconforming product and other quality problems; verifying or validating the corrective and preventive action to ensure that such action is effective and does not adversely affect the finished device." —21 CFR 820.100, Quality System Regulation
"The organization shall take action to eliminate the causes of nonconformities in order to prevent recurrence. … A documented procedure shall be established to define requirements for … determining the causes of nonconformities, evaluating the need for action to ensure that nonconformities do not recur, determining and implementing action needed … and reviewing the effectiveness of the corrective action taken." —ISO 9001:2008—Quality management systems—Requirements
1. John L. McCaffrey, "What Corporation Presidents Think About at Night," The Book of Business Wisdom, Peter Krass (ed.), Wiley, 1997.
Les Schnoll has 35 years of experience in industries regulated by the Food and Drug Administration. He earned a doctorate in health law from Kaplan University. Schnoll is a senior member of ASQ and an ASQ-certified quality engineer, auditor and manager. A member of the U.S. technical advisory group to ISO technical committee 176, Schnoll wrote The Regulatory Compliance Almanac.