Dr.SurgeonPGH said:The pattern that distinguishes a bad batch from an exit is behaviour rather than product.
I disagree that testing history is decisive. It tells you what a supplier did when they were being watched. Continuity of behaviour under stress — a late shipment, a failed test, a complaint — is more predictive than any run of good results.
DataDave said:Eight months with one supplier, then a change in how they communicate that I noticed before I noticed anything about the product.
Shipping damage protocol for vendor vetting orders: if your package arrives with visible damage, temperature excursion, or broken vials:
Reputable vendors will replace damaged shipments without argument. If they push back, that's a red flag about the vendor.
Dr.NateNeph said:I disagree that testing history is decisive.
There is a second half to this that has not been said yet. Worth answering the question that was asked rather than the one behind it. The narrow version usually has an answer; the broad version usually does not, and answering the broad one is how a thread stops being useful.
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Shop Reference StandardsA narrower follow-up, since the general answer is now clear:
How people are distinguishing a supplier having a bad batch from a supplier on the way out?
Reporting back.
Went back through my own correspondence with an earlier supplier and the warning signs were all there in the replies, weeks before the quality changed. I was reading the product and not the behaviour.