Every SME depends on suppliers: the steel merchant, the packaging, the haulage firm or the IT company. When a supplier delivers badly, customers notice first. A supplier evaluation turns gut feeling into a traceable decision: you set a few criteria, award points, calculate an overall score and derive from it how much trust the supplier deserves. This guide shows how to build a supplier evaluation in your business, how the score is arrived at and how to keep reassessment under control.
What a supplier evaluation is for
The evaluation answers three questions. First: with whom do we continue to work, and with whom only under conditions? Second: where is a conversation worthwhile because quality is falling or deadlines are regularly missed? Third: can we show customers and auditors that we keep an eye on our suppliers?
The yardstick matters. Anyone who only compares prices overlooks the follow-on costs: rework, complaints, rush deliveries. A cheap supplier who delivers every third consignment late can cost more overall than a supplier with a higher price who delivers reliably. An evaluation with several criteria makes this connection visible.
Do not evaluate all suppliers in equal depth. For ordering office supplies a short note is enough; for the supplier whose parts are built into your product, you need regular evaluation with evidence.
What ISO 9001 says
If your business works to ISO 9001 or wants to be certified, clause 8.4 is the reference point. It deals with the control of externally provided processes, products and services and is divided into general requirements (8.4.1), type and extent of control (8.4.2) and information for external providers (8.4.3). In substance, it is about setting criteria for the selection, performance monitoring and re-evaluation of external providers, aligning the control with risk and telling providers what you expect of them. As evidence, you retain the results of the evaluations.
As we understand it, this clause prescribes no particular method. Weighted points, as described here, are a widespread practical tool, not a requirement of the standard.
On the edition: The 6th edition, ISO 9001:2026, has applied since 16 September 2026 and replaces the 2015 edition. The clause numbers and descriptions of content above come from the 2015 edition and have not been checked against the text of the 2026 edition. According to a Swiss certification body, the changes overall are moderate, without a fundamental new direction. Check numbers and wording in your edition; certified companies switch within the transition period set by their certification body. This guide does not reproduce the text of the standard.
Setting criteria and weightings
Choose a few criteria that you can really assess. Five have proved their worth:
- Quality: Do deliveries match the order, and how much has to be reworked or sent back?
- Punctuality: How often do the goods arrive at the agreed time?
- Value for money: Is the ratio right, also taking follow-on costs into account?
- Communication: Does the supplier answer clearly and on time, and does it inform you of delays unprompted?
- Complaint handling: How quickly and how cleanly does it resolve complaints?
Award 1 to 5 points per criterion, where 1 means “unsatisfactory” and 5 “very good”. To keep the points comparable, record in writing what a 5 and a 1 mean. For punctuality this could look like this (an example scale, not a requirement): 5 points from 95 per cent on-time deliveries, 4 points at 90 to 94, 3 points at 80 to 89, 2 points at 70 to 79, below that 1 point.
Weight the criteria according to their importance for your business. The overall score is the weighted average: multiply each score by its weighting and divide the sum by the sum of the weightings. An example with the weightings quality 3, punctuality 2 and 1 each for the other three criteria is worked through below.
Use data where it exists: complaints that you can assign to the supplier, goods-receipt inspections, delivery reliability from your orders. The points, however, are still set by a person. A number alone does not replace judgement, for example when a supplier failed once because of a strike.
From the overall score to a status
The score is only an intermediate step. What you derive from it is decisive. A simple rule with three levels is enough for most SMEs:
- Approved: Overall score of 4 or more. The supplier is regarded as reliable, and you generally reassess once a year.
- Conditionally approved: Overall score of 3 or more but below 4. You carry on working, address the weaknesses and reassess more often, for example every six months.
- Blocked: Overall score below 3. No new orders are placed until the causes are remedied.
A minimum rule is also worthwhile: if a single criterion receives only 1 point, the supplier is at most “conditionally approved”, even if the average is good. Otherwise a good price hides a serious quality problem.
These thresholds and intervals are practice, not prescribed by law or standard. Set them for your business and record them in a short work instruction. New suppliers start with the status “new” and receive their first evaluation after the first deliveries.
Self-assessment and data protection
Not everything is visible from outside. A self-assessment asks the supplier about certificates and their validity, a contact person for quality, its delivery reliability, how it handles complaints and significant changes such as a change of site or owner. This information is self-declaration. It replaces neither a check of the certificates nor your own experience, but it is a good starting point.
If you record names, email addresses or phone numbers of the supplier’s employees, these are personal data, that is, information relating to an identified or identifiable natural person (Art. 5 lit. a DSG). Under Art. 2 para. 1, the Data Protection Act applies to the processing of personal data of natural persons. For you this means: record only what you need for the supplier evaluation, use the information only for that purpose (Art. 6, paras. 2 and 3) and delete or anonymise it when it is no longer required (Art. 6, para. 4). Inform the contact persons recorded, for example through your privacy notice, at least of your identity and contact details and the purpose (Art. 19 DSG, paras. 1 and 2); if the information comes from the supplier and not from the person themselves, also state the categories of data (Art. 19 DSG, para. 3). If the supplier is a sole proprietorship, the evaluation itself is also processing of personal data. For essential suppliers, an on-site supplier audit can supplement the self-assessment.
Practical example: Muster Metallbau AG
Muster Metallbau AG is a fictitious company. It evaluates three suppliers with the weightings quality 3, punctuality 2, value for money 1, communication 1 and complaint handling 1. The weightings add up to 8.
| Supplier | Quality (×3) | Punctuality (×2) | Value (×1) | Comm. (×1) | Compl. (×1) | Overall score | Status |
|---|---|---|---|---|---|---|---|
| Muster Stahlhandel AG | 4 | 3 | 5 | 4 | 3 | 3.75 | conditional |
| Muster Verpackungen GmbH | 5 | 4 | 3 | 4 | 4 | 4.25 | approved |
| Muster Beschichtung AG | 5 | 4 | 4 | 5 | 1 | 4.13 | conditional |
The calculation: for the steel merchant, 4 × 3 + 3 × 2 + 5 + 4 + 3 gives 30 points in total, divided by 8 gives 3.75. For the packaging firm it is 15 + 8 + 3 + 4 + 4 = 34, divided by 8 gives 4.25. For the coating firm it is 15 + 8 + 4 + 5 + 1 = 33, divided by 8 gives 4.125, rounded 4.13.
The coating firm is arithmetically above 4. But because complaint handling received only 1 point, under the minimum rule it is at most “conditionally approved”. The reason: a delivery with a colour deviation went unanswered for weeks. Muster Metallbau AG records the case as a complaint to the supplier and discusses it at the next meeting.
For the steel merchant, the punctuality score of 3 rests on ten on-time orders out of twelve in twelve months, which is about 83 per cent; under the example scale above, that gives 3 points. The evaluation took place on 15.10.2026. For the two suppliers classed as “conditional”, reassessment is planned after six months on 15.04.2027, for the packaging firm after twelve months on 15.10.2027.
Checklist
- Suppliers classified by importance (essential or minor)
- Criteria, weightings and points scale set in writing
- Thresholds for “approved”, “conditionally approved” and “blocked” defined
- Minimum rule for individual criteria with 1 point set
- Reassessment interval determined for each status
- Responsible person for the evaluation named
- Self-assessment obtained for essential suppliers
- Complaints assigned to suppliers
- Contact persons recorded only as far as necessary and purpose communicated
- Evaluations retained traceably
How KMU | base helps
In QMS | base you find the suppliers in the menu under Operations and records › Suppliers.
Supplier list with status. You keep suppliers with category, service, contact person and status: new, approved, conditionally approved or blocked. The list shows the overall score, the number of complaints and the date of the next evaluation; if it is due, “Evaluation due” appears next to it. You filter by status and search by name.
Evaluation by weighted criteria. You award 1 to 5 points for quality, punctuality, value for money, communication and complaint handling, or for criteria of your own. The default weightings are quality 3, punctuality 2 and 1 each for the others; you adjust weightings and criteria. The preview shows the overall score and a proposed status: approved from 4, conditionally approved from 3, blocked below that; a criterion with 1 point allows at most “conditionally approved”. You adopt the proposal or choose the status yourself. The software sets the date of the next evaluation itself: 12 months for “approved”, 6 months for “conditionally approved”, none for “new” and “blocked”. A status can also be overridden without a new evaluation, for example after an incident.
Supplier evaluation due. The QM manager receives a reminder on the due date. This requires the QM manager to be named in the settings.
Supplier self-assessment. With one click you request a self-assessment from the supplier (certificates, quality contact, delivery reliability, complaints, changes). The supplier answers it through a link without an account, and its answers appear with the supplier. You forward the link to the supplier yourself; QMS | base does not send it.
Suppliers linked to Finance. You link the supplier to the creditor in Finance | base; the search takes over name and email. With the supplier you then see delivery reliability over the last twelve months; it also appears in the management review.
Complaint to the supplier. A nonconformity relating to a supplier is recorded directly with the supplier, with a reference to the order, delivery note or batch. It belongs to the reports, provided you have the necessary rights.
Metrics automatically from the data. A quality objective can fetch its actual value from the supplier evaluation itself; for each supplier the latest evaluation is taken into account, and blocked suppliers are left out.
What the software does not do: People set the points by hand; neither complaints nor delivery reliability from Finance | base automatically produce a score. You maintain the suppliers in QMS | base yourself; they are not currently taken over from the shared contacts. Delivery reliability only appears if Finance | base is booked and the supplier has been linked to a creditor.
The guide to QMS | base explains how to use it. Take a look at the demo or open a trial account. If you have questions, the contact page will help.
Sources
- SNV: SN EN ISO 9001:2026, Quality management systems – Requirements, valid since 16 September 2026, replaces the 2015 edition (in German); accessed on 27.10.2026. The clause references (8.4, 8.4.1 to 8.4.3) come from the 2015 edition and have not been checked against the 2026 text.
- ISO: ISO 9001:2026 (Edition 6), published on 16 September 2026; accessed on 27.10.2026.
- SQS: ISO 9001:2026 revision of the standard – all information, accessed on 27.10.2026.
- Federal Act on Data Protection (DSG, SR 235.1), Art. 2, para. 1, Art. 5 lit. a, Art. 6, paras. 2 to 4 and Art. 19, paras. 1 to 3, as at 7 July 2025: fedlex.admin.ch (German original), accessed on 27.10.2026.
Weightings, thresholds, intervals and the example scale are editorial practical aids. They do not reproduce ISO standard text and do not demonstrate conformity for certification.
This guide does not replace legal or tax advice. Information as at 27 October 2026.