NPS and CSAT for ISO 9001: will an auditor accept them, and which should you use?
Yes, an auditor can accept either. ISO 9001 does not name a metric. What an auditor assesses is whether you defined a method, applied it consistently, collected enough to evaluate, and acted on what you found.
So the real choice is about fit. CSAT asks directly whether customers were satisfied with what you delivered, which is close to what clause 9.1.2 is about. NPS measures loyalty to the whole relationship and needs far more responses to be reliable. For most certified companies, CSAT should be the main measure and NPS an optional extra.
What an auditor actually looks at
Not which metric you chose, but whether:
- the method, including how the score is calculated, is defined and written down;
- it has been applied the same way since the last audit;
- there are enough responses, from a fair spread of customers, to support what you conclude;
- the responses behind the score can be shown on request;
- something was done about unhappy customers and the themes they raised.
A consistently collected score with the responses behind it is easy to present. A score with no underlying responses, or one calculated differently each quarter, is where findings come from. The full list is in the clause 9.1.2 audit checklist.
How CSAT, NPS and CES fit clause 9.1.2
| CSAT | NPS | CES | |
|---|---|---|---|
| What it asks | How satisfied were you with what we delivered? | How likely are you to recommend us? | How easy was it to deal with us? |
| What it measures | Perception of one delivery or interaction | The overall relationship and loyalty | Effort and friction |
| Fit with clause 9.1.2 | Direct: it asks whether the customer was satisfied with what they received | Indirect: a willingness to recommend, from which you infer that needs were met | Partial: a hard process can still deliver what was needed |
| Responses for ±10 points* | About 60 | About 235 | — |
| Best used | After each delivery, as the main measure | Once or twice a year, per account | Alongside CSAT, where process friction matters |
*For a score you can trust to within 10 points either way, at a 95% confidence level, with CSAT around 80% and NPS around +30. The working is in CSAT vs NPS.
Which to use
Make CSAT the main measure
Ask it after each delivery, project or service visit. It is the closest match to what the clause asks, it reaches a usable precision with far fewer responses, and when it drops it points at a specific delivery you can look into. Report it as the percentage of customers choosing 4 or 5 on a 1–5 scale, and write that calculation into your method.
Add NPS only if you have the volume
NPS is a fair measure of the relationship, but it needs roughly four times as many responses as CSAT for the same precision. Many certified companies, especially those selling to other businesses, have a few dozen active customers, not a few hundred. At that volume NPS swings by tens of points from one quarter to the next without anything changing, and explaining those swings to an auditor is harder than not having them. If you do use it, ask once or twice a year, per account, rather than after every delivery.
Always ask why
Whichever score you choose, pair it with an open question for unhappy customers. The reason is what you act on, and it is what connects clause 9.1.2 to your complaint handling under clause 10.2. The 9.1.2 survey template is built this way.
Pitfalls that make a score hard to defend
- Changing the scale. Moving from 1–5 to 1–10, or rewording the question, breaks the comparison with every earlier period. If you must change it, record when and why.
- Setting a target before a baseline. A satisfaction objective under clause 6.2 is a good idea, but set it after a few months of data, not before. A target picked from a benchmark you cannot compare yourself to invites a miss you then have to explain.
- Writing NPS as a percentage. NPS runs from −100 to +100. “An NPS of 40”, never “40%”.
- Comparing across languages. People use rating scales differently across languages and cultures, so compare each language against its own history.
The general comparison is in the NPS vs CSAT vs CES guide, and what to do when the two scores disagree is in CSAT vs NPS.
Questions about metrics for ISO 9001
Is NPS an ISO 9001 requirement?
No. ISO 9001 does not require NPS, CSAT or any other named metric. It requires you to monitor customer perception by a method you have decided.
Can customer satisfaction be a quality objective?
Yes. Objectives under clause 6.2 need to be measurable and monitored, and a CSAT target measured every quarter meets both. Base the target on your own history rather than on another company’s number.
Do we need all three metrics?
No. One well-run measure with the reasons behind it is better evidence than three half-run ones. Customer Feedback Simplified supports all three on every plan, so you can start with CSAT and add NPS or CES later without changing tools.
Should the score go into the management review?
Customer satisfaction is a listed input to management review under clause 9.3.2, in the 2015 and 2026 editions alike. Bring the trend, what moved it, and what was done, not just the latest number.
Related guides
- ISO 9001 clause 9.1.2 customer satisfaction evidence (2015 and 2026)
Where the product fits in your QMS, and what it does not do.
- Clause 9.1.2 customer satisfaction survey template
The questions to ask, on which scale, and why each one earns its place.
- Clause 9.1.2 audit checklist
What an auditor looks for, the questions they ask, and where findings come from.
- How to write your 9.1.2 procedure
A method statement you can adapt: who is asked, how, how often, and what happens next.
Clause numbers on this page are the same in ISO 9001:2015 and ISO 9001:2026, except in clause 10: what was 10.3 (continual improvement) in 2015 is 10.1 in 2026, and the 2015 edition’s 10.1 (general) is merged into it. Nonconformity and corrective action is 10.2 in both. ISO 9001:2015 certificates are expected to remain valid until 30 September 2029 (subject to confirmation by the accreditation bodies). From around 31 March 2028, new certifications are issued to ISO 9001:2026 only. Confirm dates with your certification body.
Clause details are based on published summaries of ISO 9001:2026; verify against the standard before relying on them. Requirements are paraphrased on this page, not reproduced, and your certification body’s reading is the one that counts. Last reviewed 2026-09-30.
Evidence that collects itself
Customer Feedback Simplified runs your satisfaction questions continuously, per location, and keeps every response with its date. When a response matches a rule you set, a browser notification arrives with the customer’s words attached; you record what was done about it, and the export puts that record beside the score.
No card required.