Partially effective CAPA

Chrisx

Quite Involved in Discussions
Anyone have experience closing a CAPA where the corrective action significantly reduced the incident of a defect, but did not completely eliminate it. I believe I can demonstrate a significant decrease in the frequency of the nonconformity. I'm not confident in my case that we are going to be able to completely eliminate the defects. Is this approach likely to pose issues in audits and FDA inspections?
 

William55401

Quite Involved in Discussions
you should’ve had an acceptance criteria defined and approved before you implemented the action plan. Predetermined acceptance criteria. that’s part of CAPA planning.

waiting at this point to decide if it’s good enough is not a good practice. you run the risk of flinching to say “yeah it’s good enough”. does your procedure require predetermined acceptance criteria?

Will the agency have an issue? it really depends. Does this relate to your product performance or safety?
 

Miner

Forum Moderator
Leader
Admin
This can occur when there is more than one cause for the issue and your corrective action only addressed one of those causes. I have experienced this in a non-medical setting. We used a Fault Tree Analysis to determine the other causes then generated corrective actions for those.
 

Bev D

Heretical Statistician
Leader
Super Moderator
you should’ve had an acceptance criteria defined and approved before you implemented the action plan. Predetermined acceptance criteria. that’s part of CAPA planning.

waiting at this point to decide if it’s good enough is not a good practice. you run the risk of flinching to say “yeah it’s good enough”. does your procedure require predetermined acceptance criteria?

Will the agency have an issue? it really depends. Does this relate to your product performance or safety?
In my experience there is often a ‘baseline’ defect rate for things and then a new causal mechanism occurs greatly increasing the defect rate. I have typically stated that the Corrective Action (there is no such thing as a CAPA; this is misappropriation of a term from the early days of ISO when Corrective Actions and Preventive Actions were separate) would return the defect rate to it’s baseline or historical rate. Of Course I use Control Charts for these things so it’s relatively easy. I’ve never had difficulty with this approach. There are some Problems that may have two or more distinct causal mechanisms in play and I’ve seen these too. In these cases, when controlling for one mechanism doesn’t complete the required reduction, I have required continued investigation to finish the job.
 

Bev D

Heretical Statistician
Leader
Super Moderator
We can be much more helpful if you can describe the situation…We have all seen cases where someone ‘solves’ a problem but the corrective action is only implemented coincidentally with a natural lo point in the defect rate and then the rate goes back up because the corrective action was wrong or only addressed a minor cause…
 

QuinnM

Involved In Discussions
Hi, I'm under the impression your CAPA is in the effective phase, so my comment my not aid the current situation. We had a CAPA where obtaining root cause was difficult, that is pin pointing root cause was impossible. We had lots and lots of data during the investigation, so we pareto the data and then eliminated the top 20% of issues we found. This approach was identified as part of our root cause investigation, rather than the effectiveness check. I can't remember what the effectiveness check was. The product was for a class III medical device, and this did not have issues with the FDA or notified bodies.
 

Hi_Its_Matt

Involved In Discussions
I'm shocked that @Bev D didn't mention this, but technically speaking, you can't prove that the possibility of particular defect has been eliminated. (Unless of course you eliminate the part/component on which the defect materializes, or you change your process to eliminate all causes of the defect). Statistically, you can only demonstrate that the likelihood of the defect has been reduced to a certain amount. That amount may be 1 in a thousand, 1 in 10k, or even 1 in 1 million. Your test sampling plan will dictate the AQL/reliability and confidence level you can claim.

So all of that goes to say, I think @William55401 and Bev provided great advice. You should have a pre-determined effectiveness acceptance criteria. If you have sufficient historical data, you can probably justify (and demonstrate) a return to, or improvement beyond, the original defect rate. If you don't have that historical data, and/or you haven't defined a certain reliability/confidence level as being acceptable, then you may just have to present your post-improvement data, and have a cross-functional decision made regarding the effectiveness of actions. That decision should be based on risk and some established precedent. For example, ISO 14971 requires manufacturers to (1) establish a policy for determining acceptable risk, and (2) document criteria for the acceptability of both individual risks and overall residual risk. You can should be able to draw some conclusion based on those.
 

Jen Kirley

Quality and Auditing Expert
Leader
Admin
Here's your snarky remark: If the NC was about 10 babies getting dropped on their heads in the delivery room and your CAPA has managed to reduce that to two babies getting dropped on their heads, how do you think the FDA would view closing based on that?

Okay, I am sure your example was not mine, but I don't know what kind of defect this was or if it was going to the customer. What was your effectiveness check criteria? You should not allow yourself to close while falling short of that.

If you truly cannot eliminate the defect, I hope it is not a safety defect and I hope you have good containment so it does not get to the customer.
:2cents:
 
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