Use in-house sorting for small, contained problems you can staff without pulling production; use an independent third party when the volume is large, the customer requires independence, the site is far from your plant, or credibility is on the line. Most escapes at the Kentucky Truck Plant end up needing a third party at some point, because CS2 requires it and because pulling your own people onto a sort quietly creates a second quality risk on the line.
The real cost of in-house sorting
In-house sorting looks free because you already pay the people, but it rarely is. Operators pulled to sort are not building parts, overtime climbs, and tired inspectors miss defects, which is how a contained problem becomes a repeat escape. In-house also lacks the independence the customer trusts, so the data may not satisfy a CS2 requirement at all.
When a third party is the right call
An independent crew brings surge capacity, trained inspectors, and objective documentation, and for CS2 it is mandatory. At the plant, a local third party can be on site the same hour, hold the gate around the clock, and keep your production team on production. The data they produce is customer-ready because it is independent, which shortens the path to exit.
A practical decision rule
Ask three questions: does the customer require independence, can you contain this without stealing hours from production, and is speed to the plant critical? If any answer points outward, use a third party. Many suppliers run a hybrid, using their own team for known low-volume checks and an independent partner for spikes, plant-site containment, and anything the OEM is watching.