Third-party inspection in China, explained properly
What pre-production, DUPRO and pre-shipment inspections actually check, how AQL sampling decides pass or fail, what a report will and will not tell you, and the one piece of sequencing that turns an inspection from a receipt into leverage.
The sequence is the whole control
Almost everything written about inspection is about what gets checked. The thing that actually decides whether an inspection protects you is when it happens relative to your money.
An inspection carried out after the balance payment has cleared is a report about a decision you have already made. The same inspection, on the same goods, booked before the balance moves, is the reason a factory fixes the problem. Nothing else on this page matters as much as that one ordering.
The second thing that matters is who the inspector's client is. A report commissioned and paid for by the factory may be perfectly honest. It is still written by someone whose customer is the person being inspected. We engage SGS on our client's behalf and pass the fee through, so the person holding the clipboard is working for the buyer.
Quality control in Chinese manufacturing: four points where a problem is still cheap
Not every job needs all four. Every job should be a deliberate decision about which ones it is skipping, rather than defaulting to a single check at the end.
Pre-production
Materials, components and trims are checked against the approved sample and the spec, and the first-off units are pulled. This is the cheapest possible moment to find that the resin grade is wrong or the fabric weight is under.
Skipped most often, and it is the one that saves the most money when it catches something.
During production
Units already made are inspected while there is still a run left to correct. A defect found here is a process adjustment. The identical defect found at the end is a rework bill or a new run.
The stage that turns an inspection program from a report into a control.
Pre-shipment
The full AQL sample is drawn from finished, packed goods: workmanship, function, measurements, labeling, barcodes, packaging and carton drop where it applies.
The last moment a problem is still cheap. After this the goods are on water.
Container loading
Carton counts verified, condition checked, load photographed and the container seal number recorded against the packing list.
Catches short shipments and damage that would otherwise be discovered, and disputed, six weeks later at a US dock.
Critical, major, minor, and why the middle one is the argument
Every inspection sorts what it finds into three buckets, and each bucket gets its own acceptance limit. The convention across consumer goods is 0 for critical, 2.5 for major and 4.0 for minor.
Renders the product unsafe or unlawful to sell: a sharp edge on a child's toy, a missing safety certification mark, a battery that vents.
Zero tolerated. One critical defect in the sample fails the lot.
Would cause a return, a refund or a complaint: it does not work, a part is missing, the color is visibly off the approved sample.
The number most buyers should be arguing about, because it is the one that maps to your return rate.
A departure from the spec that most customers would not return the product over: a slightly loose thread, a small print registration shift.
Loosening this is a legitimate way to keep a supplier's price honest. Loosening the major limit is not.
Agreeing these three numbers before production is a five-minute conversation. Not agreeing them means that when a report says "failed", you and the factory can both be sincerely surprised, because you were holding different definitions of the word.
How the sample size and the pass mark are actually decided
AQL is not a quality target. It is a statistical acceptance rule agreed in advance: draw this many units from the lot, and if this many or fewer fail, accept it. Below is General Inspection Level II under ANSI/ASQ Z1.4, which is the default almost every inspection in this industry runs at.
| Lot size | Code | Sample | AQL 2.5 (major) | AQL 4.0 (minor) |
|---|---|---|---|---|
| 151 – 280 | G | 32 | 2 / 3 | 3 / 4 |
| 281 – 500 | H | 50 | 3 / 4 | 5 / 6 |
| 501 – 1,200 | J | 80 | 5 / 6 | 7 / 8 |
| 1,201 – 3,200 | K | 125 | 7 / 8 | 10 / 11 |
| 3,201 – 10,000 | L | 200 | 10 / 11 | 14 / 15 |
| 10,001 – 35,000 | M | 315 | 14 / 15 | 21 / 22 |
Reading one row: an order of 4,000 units falls in the 3,201 to 10,000 band, which is code letter L, which means the inspector pulls 200 units. If 10 or fewer carry a major defect the lot is accepted; at 11 it is rejected. Minor defects are counted separately against their own limit.
Two things worth knowing. A lot can pass and still contain defects, because 200 units is a sample and not the whole run. And tightening the major limit below 2.5 raises your price, because the factory has to price the risk of a rejection, so tighten it where the defect would actually cost you a customer and leave it alone where it would not.
Confirm the exact plan with your inspection body before production. Level, sampling type and normal-versus-tightened inspection all change these numbers, and the standard is the authority, not this page.
What you should get back, and what it cannot tell you
A pre-shipment report should contain the quantities actually produced and packed, the sample size drawn, defects found and classified with photographs, the measurement checks against your spec, the on-site function tests, barcode and label verification, carton dimensions and weights, and a stated overall result against the AQL you agreed.
What it cannot tell you is how the product will behave in six months. An inspector checks conformity to your specification on the day; a specification that does not mention the thing that later fails will produce a clean report and an unhappy customer. That is a reason to write a real spec, and a reason to run lab testing where a claim depends on it, rather than a reason to distrust inspection.
Frequently asked
Who pays for the inspection?
You do, through us, and that is the point. An inspection the factory arranged and paid for is a document written by someone whose client is the factory. It may be entirely honest and it is still the wrong incentive structure to rely on. We engage SGS on your behalf and the fee is passed through with the quote shown to you.
What does an SGS or other third-party inspection cost?
Inspection companies price per man-day, and the number of man-days depends on the sample size, the complexity of the checks and where the factory is. We show you the inspector's quote rather than marking it up, so the honest answer here is that we will get you the actual number for your actual job rather than publishing a range that will not apply to it.
Is an inspection the same as a factory audit?
No, and confusing them is common. An audit assesses the factory: its systems, capacity, certifications and social compliance. An inspection assesses your goods. A factory can pass an audit and still ship you a bad run, and a workshop with no certifications at all can produce a flawless one. You generally want the audit once, before you commit, and the inspection on every production run.
What happens if the inspection fails?
That depends entirely on what you agreed before production started, which is why we push to have it written down while everyone is still friendly. Normally: the factory reworks at its own cost, a re-inspection is booked, and the balance payment does not move until it passes. If none of that was agreed in advance, you are negotiating from a much weaker position with goods already made.
Can I just rely on the factory's own QC report?
You can look at it. You should not depend on it. Most decent factories do run internal QC and their reports are often broadly accurate. The problem is that you have no way to tell the accurate ones from the optimistic ones without an independent check, and the cost of being wrong is a container.
What does AQL 2.5 mean?
That you will accept a lot whose true defect rate is around 2.5 percent for major defects. It is a statistical acceptance limit on a sample, not a promise that 2.5 percent of your units are bad. A lot can pass at AQL 2.5 and contain defects, and a lot can fail on an unlucky sample. It is the industry's agreed way of deciding, in advance and in writing, what 'good enough' means.
Can you handle compliance testing at the same time?
Yes, and the scheduling is the reason to do it together. Compliance testing has to be carried out on production units rather than on a sample, which puts it in the same window as pre-shipment inspection. We set out what applies by product category in our guide to US product compliance for importers.
Do you inspect outside China?
Yes. We source from wider Asia, Mexico, Europe and Canada as well, and the same three-stage structure applies. The inspection body and the travel cost change; the sequence does not.
We book it, we read it, we hold the balance
Booking the inspector is the easy part. Agreeing the defect classification in advance, being on the phone when a result comes back marginal, and holding a payment while a factory reworks is the part that decides whether the inspection was worth paying for.