Why Do Testing Laboratory Quotes Differ So Much?

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Send the same product, the same standards and the same target market to three laboratories, and you will often get three numbers that are hard to reconcile. The lowest one is sometimes less than half the highest. It is tempting to read that as one lab being expensive and another being competitive.

In most cases it is not a pricing difference at all. It is a scope difference. Each quotation is a description of the work the laboratory understood it was quoting, and if the three descriptions are not the same job, the totals were never comparable. Before choosing, you need to check whether they are quoting the same thing.

A quotation is a scope document with a total at the bottom

The price follows from how much work is in scope: how many configurations, how many standards, how many sample hours, how much engineering time, and how much of the documentation work the laboratory does for you. Change any of those and the number moves - often by a factor of two or three, without anyone's margin changing at all.

This is why "why is this one cheaper" is usually the wrong question. The useful version is "what did this quote leave out that the other one included".

The differences that create most of the gap

1. How many configurations are inside the price

A product family is rarely one configuration. Different adapters, different antennas, different colour or capacity variants, a version with and without a battery. Testing every variant costs far more than testing the worst case and covering the rest by technical justification. Some laboratories price one configuration and note that additional variants are quoted on request; others price the whole family up front. Both quotes can be honest, and they are not the same job.

2. Radio tested at module level or at host level

If the design uses a pre-approved Wi-Fi or Bluetooth module, one laboratory may quote radio testing based on that module's existing approval. That is only valid when the module is installed exactly as its approval allows - the same antenna type, within the approved power settings. Change the antenna or the enclosure and the host generally needs its own radio evaluation. The cheaper quote here is not a discount, it is a narrower assumption, and it only works if the assumption is true.

3. Pre-testing, or straight to the formal run

Some laboratories include a pre-compliance scan or an engineering review before the formal test. Others quote the formal test only. On a product that has never been tested, a first-run failure on radiated emissions or a safety construction issue can mean a second invoice and a schedule reset. A quote that includes pre-testing time usually costs more at the start and less in total.

4. Whether a retest is inside the number

Two quotes can look very different simply because one assumes the product passes on the first attempt and one prices a retest window. Read the terms: is one retest cycle included, within what time limit, and what counts as a new test.

5. Which route the report takes

Test reports and certification routes are priced differently, and mixing them up produces misleading comparisons:

• A test report against the relevant standards, issued in the laboratory's name or the client's, is the base case for EMC, safety and RoHS work.
• US radio transmitters need Certification through a Telecommunication Certification Body, which produces an FCC ID. That filing step is real work with real cost, on top of the testing, and does not exist in a Supplier's Declaration of Conformity project.
• EU radio products can need a Notified Body assessment when harmonised standards are not applied, or only partly applied. Where that applies, a quote without it is incomplete rather than cheap.

One quote covering testing only, and another covering testing plus the authorization step, will never match on price. Check which one you are looking at.

6. Which laboratory signs the report

Accreditation is scoped, not general. A laboratory can be accredited to ISO/IEC 17025 for some standards and not others. A report issued under accreditation for the specific standard carries credibility that an unaccredited internal report does not, and buyers, marketplaces and authorities increasingly check it. If a report gets rejected and has to be redone elsewhere, the saving evaporates - which happens most often on projects where the buyer's compliance team reviews documents properly.

7. Everything that sits outside the number

Quotations differ just as much in what they exclude. These items appear on some quotes and not others:

Item	Often excluded by the lowest quote
Test plan and scope review	Yes - client is expected to specify the standards
Sample modification or debugging support	Yes - billed as extra engineering time
Retest after a failure	Yes - quoted separately per occurrence
Technical file structure and Declaration of Conformity drafting	Yes - testing only, documents are the client's job
Manual and label review	Yes - not part of a test-run fee
Report revision or reissue after the fact	Yes - charged per revision
Express scheduling or overtime slots	Yes - standard duration only
Sample return, storage or disposal	Yes - client arranges

None of these are hidden fees. They are simply outside the scope that was priced, and a client comparing totals without reading them is comparing the wrong numbers.

Situations that show up over and over

The RFQ described the product, not the project. A request went out as "EMC testing for CE" for a mains-powered device. One laboratory scoped EMC only, exactly as asked. Another, reading the same email, priced EMC plus the safety standard that a mains product needs for CE - because without it the file would not support the marking. The second quote was higher and closer to what the customer actually needed. The fault was in the enquiry, not in either laboratory.

The variant list was decided after the quote. A quote was built around a single sample. By the time the project started, the product would ship with two different power adapters and three colour variants. The laboratory re-quoted, because the adapter is part of the tested configuration and can change emissions and safety results. Nothing unusual happened - the scope simply grew. It grows less painfully if the variant list is settled before the first quotation is requested.

Samples that do not match the production build. A project was quoted on the basis that the client would supply final production samples. The samples that arrived were engineering units with a different firmware build and one component changed for availability. The laboratory flagged the mismatch, because the report would describe hardware that nobody would sell. Testing was held while the build was corrected. This is a scope problem that shows up as a delay rather than an invoice, and it is one of the reasons some laboratories spend more time on sample verification up front.

The cheapest quote and the first-run failure. A product failed radiated emissions on its first formal run at a laboratory that had quoted the formal test only. The rework, the retest and the rescheduled slot cost more than the difference between that quote and the one from the laboratory that had included a pre-compliance scan and engineering feedback. On a mature product the gamble sometimes pays off. On a first design it usually does not.

How to compare quotations properly

1. Ask for the scope in writing. Standards and versions, test items, number of samples, number of configurations, expected duration, and a list of what is not included.
2. Build a comparison table before comparing prices. One row per scope item, one column per laboratory. Gaps in the table are the answer.
3. Confirm the report route and who accepts it. Ask your buyer, marketplace or the authority's requirement which route they need - testing, certification, or a Notified Body assessment - and match the quote to that, not the other way round.
4. Ask what happens after a failure. Included retest, extra cost, or new project. Get the number in writing.
5. Check the scope of accreditation for the standards involved, especially if the report goes into a technical file or a compliance review.
6. Ask what triggers a re-quote - changed firmware, changed adapter, added variant, changed standard version. A laboratory that answers this clearly usually also scopes clearly.

Why a higher quote is sometimes the cheaper one

A quotation that includes a scope review before sample arrival, sample verification on receipt, a pre-compliance pass, engineering feedback on what failed, and a structured technical file costs more to produce than a formal test slot. The return is that the project finishes with documents your buyer accepts, without a second invoice in month three.

That is the difference we build into how we quote at our laboratory in Shenzhen. If you want the scoping checklist we use, the testing and certification services pages set out the standards and test items by service line, and the breakdown of a testing quotation explains each line item, so you can read a competitor's quote next to ours item by item rather than comparing two totals that were never describing the same work.