How can you tell whether a CAPA was effective?

Why

Build the effectiveness check from the investigation hypothesis. Suppose a recurring wrong-aliquot problem arose from ambiguous bench labels. Define a corrected labeling control, check that it is installed and then independently sample routine work to verify the error pathway is closed.

Establish observation window, workload denominator, pass criteria and escalation before seeing the results. Use a direct challenge or simulated stress case when real errors are too rare to estimate recurrence reliably. Include unintended effects, such as a new barcode rule causing specimen delays.

Audit trail and independent reviewer evidence should support conclusions. If the signal reappears, investigate whether the root cause, action or measurement method was wrong. Documentation completion is a necessary workflow step, never a substitute for effectiveness.