Supplier capability assessment: what to check and how to score it
How to assess whether a supplier can deliver the required quality, quantity and on time: the areas to check, the scoring scale, critical questions, risk classes and when to go on site.
What a supplier capability assessment is
A supplier capability assessment answers one question before you award business or when risk changes: can this supplier deliver parts that meet the requirements, in the required quantity, on time, and keep doing so? It looks at the management system, the processes and the evidence behind them, not at a sales presentation.
It is required in practice by IATF 16949 clause 8.4.1.2 (supplier selection process) and 8.4.2.4 (supplier monitoring), and by most customer-specific requirements.
When to assess
- Before nominating a new supplier or a new site of an existing supplier.
- When a supplier takes on a new technology, product family or a big volume increase.
- After a serious quality incident, a change of ownership or key management.
- Periodically for high-risk suppliers, as part of the audit plan.
The areas to cover
| Area | Typical questions |
|---|---|
| Quality management system | ISO 9001 / IATF 16949 certificate, internal audits, management review, customer-specific requirements known |
| Product and process development | APQP, FMEA, control plans, special characteristics, PPAP or PPF capability |
| Production and process control | Work instructions, SPC on critical characteristics, Cpk, error proofing, first-part approval, maintenance |
| Measurement and testing | Calibration, MSA (Gage R&R), lab scope, measurement capability for your tolerances |
| Nonconformity and improvement | Containment, 8D, lessons learned, handling of nonconforming product, traceability |
| Supply chain and logistics | Sub-supplier management, capacity, delivery performance, packaging, contingency plans |
Scoring and risk class
Rate each question on a fixed scale, for example 0 (not in place), 1, 2, 3 and 4 (effective and proven by records). Calculate the result per area and overall as a percentage of the maximum. A typical rule: class A from 85 % with no area below 70 %, class B from 70 %, class C below 70 %.
Mark a few questions as critical: certification, change approval, control of special characteristics, nonconforming product, calibration, complaint handling and traceability. A 0 on any critical question limits the result to class C regardless of the total.
Evidence makes the result defensible
Every rating needs evidence: a document, a record or an observation. "Yes, we do SPC" is not evidence; a control chart from last week with reactions to out-of-control points is. Write the evidence next to the rating so that the next assessor can follow it.
Desk assessment vs on-site audit
A self-assessment questionnaire is a fast first filter and works well for low-risk parts. For safety or functional parts, new technologies and class C results, follow up on site with a process audit (for example VDA 6.3 potential analysis P1 for new suppliers, or the full P2–P7 process audit) and check capability data of the actual process.
Written by Ľubomír Blažek, automotive quality manager. Standards are summarised in our own words; use the official publications for formal work.