This is how I interpret verification vs. validation, however, some people have disagreed with me.
Verification - is it being done according to the standard procedure - frequency, log sheets, correct tools & supplies, etc?
This could be done by signed audits, or supervisors/dept. managers reviewing/auditing the log sheets and signing as evidence they reviewed.
Log Sheets and/or Supervisor signature verify that the procedure is being done.
No audit or review = no guarantee that it is being done (no verification).
Validation - is the standard procedure actually working to control the problem?
Management review of audit trends, corrective actions, non-compliances, customer complaints, test data, etc.
Document the management reviews - who, when, what was decided, correction actions, etc.
No meeting minutes or report = no evidence of validation.
Silly example - employees on each shift do a quality/food safety dance (similar to a rain dance):
Verification - yes, employees are dancing on each shift. I see them do it every day.
Validation - no, not working. Still having the same problems. Dancing is totally invalid (ineffective).
More realistic example - employees required to wash hands at certain times.
Verification - no one is checking if employees are washing their hands.
Validation - already commonly known that washing hands is effective in preventing cross contamination from people to products.
(This may have been part of the reason for the problems that Chipotle's was having).