This blog reviews the differences between corrective action and preventive action, and when to initiate corrective and preventive action.
I’ve completed almost 100 audits in the past two years, and I review the Corrective Action and Preventive Action (CAPA) process during every single audit. Surprisingly, this seems to be a process with more variation from company to the company than almost any other process I review. This also seems to be a major source of nonconformities. In the ISO 13485 Standard, clause 8.5.2 (Corrective Action) and clause 8.5.3 (Preventive Action) have almost identical requirements. Third-party auditors, however, emphasize that these are two separate clauses. We are purists. Although we acknowledge that companies may implement preventive actions as an extension of corrective action, we also expect to see examples of actions that are strictly preventive in nature.
Many companies seem to be confused, but it doesn’t need to be. Just ask yourself one question. What is the source of this action?
If the answer is a complaint, audit nonconformity, or rejected components—then your actions are corrective.
If the answer is a negative trend that is still within specifications or an “Opportunity For Improvement” (OFI) identified by an auditor—then your actions are preventive.
Root Cause Investigation
If you are investigating the root cause of a complaint, people will sample additional records to estimate the frequency of the quality issue. I describe this as investigating the depth of a problem. The FDA emphasizes the need to review other product lines, or processes, to determine if a similar problem exists. I describe this as investigating the breadth of a problem. Most companies describe actions taken on other product lines and/or processes as “preventive actions.” This is not always accurate. If a problem is found elsewhere, actions taken are corrective. If potential problems are found elsewhere, actions taken are preventive. You could have both types of actions, but most people incorrectly identify corrective actions as preventive actions.
Another common mistake is to characterize corrections as corrective actions.
The most striking difference between companies seems to be the number of CAPAs they initiate. There are many reasons, but the primary reason is the failure to use a risk-based approach to CAPAs. Not every quality issue should result in the initiation of a formal CAPA. The first step is to investigate the root cause of a quality issue. The FDA requires that the root cause investigation is documented, but if you already have an open CAPA for the same root cause…
DO NOT OPEN A NEW CAPA!!!
If you do not have a CAPA open for the root cause that you identify, then what should you do?
I know this will shock everyone, but…it depends.
The image below gives you my basic philosophy.
Most investigations document the estimated probability of occurrence of a quality issue. This is only half of the necessary risk analysis I describe below. Another aspect of an investigation is to document the severity of potential harm resulting from the quality issue. If customer satisfaction, safety, or efficacy are affected by a quality issue—the severity is big. Risk is the product of severity and probability of occurrence.
Estimated Risk-Initiating a Corrective And Preventive Action (CAPA)
If the estimated risk is low and the probability of occurrence is known, then alert limits and action limits can be statistically derived. These quality issues are candidates for continued trend analysis—although the alert limit or action limit may be modified in response to an investigation. If the trend analysis results in identifying events that require action, then that is the time when a formal CAPA should be opened. If the trend remains below your alert limit, then no formal CAPA is needed.
If the estimated risk is moderate or the probability of occurrence is unknown, then a formal CAPA should be considered. Ideally, you will be able to establish a baseline for the occurrence and demonstrate that frequency decreases upon the implementation of corrective actions. If you can demonstrate a significant drop in frequency, this verifies the effectiveness of actions taken. If you need statistics to show a difference, then your actions are not effective.
If the estimated risk is high, or there are multiple causes that require multiple corrective actions, a quality improvement plan may be more appropriate. There are two clauses in the Standard that apply. Clause 5.4.2 addresses the planning of changes to the Quality Management System. For example, if you correct problems with your incoming inspection process—this addresses 5.4.2. Clause 7.1 addresses the planning of product realization. For example, if you correct problems with a component specification where the incoming inspection process is not effective, this addresses 7.1. Depending upon the number of contributing causes and the complexity of implementing solutions, the plan could be longer or shorter. If it will take more than 90 days to implement corrective action, you might consider the following approach.
Step 1 – open a CAPA
Step 2 – identify the initiation of a quality plan as one of your corrective actions
Step 3 – close the CAPA when your quality plan is initiated (i.e., – documented and approved)
Step 4 –verify effectiveness by reviewing the progress of the quality plan in management reviews and other meeting forums…you can cross-reference the CAPA with the appropriate management review meeting minutes in your effectiveness section
If the corrective action required is the installation of new equipment and validating that equipment, the CAPA can be closed as soon as a validation plan is created. The effectiveness of the CAPA is verified when the validation protocol is successfully implemented and a positive conclusion is reached. The same approach also works for implementing software solutions to better manage processes. The basic strategy is to get the long-term improvement projects started with the CAPA system, but monitor the status of these projects outside the CAPA system.
Best practices would be the implementation of six-sigma projects with formal charters for each long-term improvement project.
NOTE: I believe in closing CAPAs when actions are implemented, and tracking the effectiveness checks for CAPAs as a separate quality system metric. If closure takes more than 90 days, the CAPA should probably be converted to a Quality Plan. This is NOT intended to be a “workaround” to give companies a way to extend CAPAs that are not making progress in a timely manner.