Just some "thoughts" - there are many ways to approach this:
Counting to determine the magnitude - and assessing the risk in realistic terms.
Example 2 parts of 5,000 may or may not be large enough to justify "documented correction" UNLESS the 2 defectives have an underlying life-safety criticality attached to it. - which increases the liability risk to the producer.
A level can be set at 0.5% per lot (or whichever size & % your management is comfortable with) as a "threshold" level indicating a documented action should take place.
If the root cause of a problem "occurs 4 times weekly" obviously there is a high level of risk of re-occurance, until documented correction can settle the matter.
(For example) If we produce 10,000 parts and 2 are found 0.05mm short of specified legnth
the magnitude and risk of re-occurance is viewed here as not being justified for documented actions.
Probably did not answer your question entirely - but possibly others have a better viewpoint - or other approaches to a complex wide open for interpretation standards statement.