A supplier rating is a summarized assessment of supplier performance, risk or suitability based on defined evidence and criteria. It may be numeric, categorical or both.
How can a rating be calculated?
Assume quality has a 50% weight with a score of 88, delivery has 30% with a score of 80, and service has 20% with a score of 90. The weighted rating is 88 × 0.50 + 80 × 0.30 + 90 × 0.20 = 86.
Illustrative supplier rating
| Category | Weight and score | Weighted points |
|---|---|---|
| Quality | 50% × 88 | 44 |
| Delivery | 30% × 80 | 24 |
| Service | 20% × 90 | 18 |
| Total rating | 100% | 86 |
The rating is meaningful only when formulas, periods and data are consistent.
Rating vs. supplier evaluation
An evaluation is the broader assessment process. A rating summarizes its result or ongoing performance. Mandatory failures should not be hidden by a strong average.
How should rating bands be governed?
Define thresholds, evidence, review frequency and actions for each band. Explain whether the rating measures performance, risk, qualification or a combination.
What should users avoid?
Do not mix old and current data, penalize buyer-caused failures or compare suppliers with materially different scopes without adjustment.
