Hiring a quality service provider usually happens at the worst possible time: there is material that needs to be retained, the client is waiting, and the decision is made with the information available to them, which is almost always an hourly rate.
The rate is the least useful data point of all. These are the ones that matter.
Compliance: The Non-Negotiable
Current REPSE Registration, It is not only valid, but also includes the legal purpose and the corresponding registered activities for the contracted service. A registration that covers different activities does not provide protection.
Along with that, the tax compliance opinion in good standing with the SAT, the IMSS compliance opinion, and the Tax Status Certificate (Constancia de Situación Fiscal) updated.
Without that complete file, the contracting plant is exposed to joint liability for the labor obligations of the supplier's personnel, and the expense may not be deductible.
Criterion: What Counts as a Defect
Two suppliers with the same rate can deliver incompatible results if they apply different criteria.
Ask how they document the criteria before starting. If the answer is that “the supervisor explains them to the inspectors”, the criteria do not exist: there is each person’s interpretation. What should exist is a written work instruction, with physical samples of the limit when the defect is visual, signed by both parties.
A poorly defined criterion produces two costs. Good material rejected, which is a direct loss. And bad material released, which is a problem at the customer's plant.
Traceability: How to Prove What Was Done
An inspected part and an uninspected part look the same.
Ask how they identify inspected material. If there is no verification mark on the individual part — color dot, label, stamp — the only evidence of the service is a report about the lot. When a complaint comes in about a specific unit, that report will not answer it.
Scaling Capacity and Response Time
A containment service rarely stays at the size it started with. Ask where the additional staff comes from when you have to go from three inspectors to ten in one day.
And ask where the provider's base is located. A provider operating from another state may quote cheaper per hour and cost more in total, because the material remains retained while their staff arrives and because the supervision will be remote.
Report: What Information They Return
The minimum report says how many parts were checked and how many were defective. That report credits hours worked and is useless for anything else.
The useful report segments: by turn, by lot, by defect type, by position in the queue. That information feeds the root cause analysis, and is not reconstructed afterwards — it is captured while inspecting or when it is lost.
If the provider is going to be part of the solution and not just the containment, the reporting is where it is noticeable.
System certification
ISO 9001:2015 With coverage that covers the contracted services. A certificate stating otherwise does not certify the service you are purchasing.
