A low quotation is useful only when the supplier can make the right product repeatedly. Use four approval gates: specification, identity and capability, representative quality evidence, then a controlled pilot.
Practical frameworks are editorial recommendations. All worked examples are hypothetical, not client results. Confirm transaction-specific legal, tax and safety requirements with a qualified professional.
1. Send one specification to every bidder
Issue a versioned request for quotation. A supplier must mark each requirement as met, not met or requiring clarification. Resolve exceptions before comparing prices.
- Include material grade, drawings, tolerances, test method, packaging, required documents, order quantity and the named delivery point.
- Separate mandatory requirements from preferences. A failed safety-critical or regulatory requirement cannot be offset by a lower price.
2. Verify who makes, sells and receives payment
Match the contract entity, manufacturing site and proposed payment beneficiary. An intermediary is not automatically unsuitable, but responsibility for quality and delivery must be explicit.
- Verify registration through the relevant official registry; confirm certificate issuer, scope, site and expiry rather than accepting a logo.
- Ask for the production process, constrained equipment, capacity evidence and subcontracted operations. Independently verify changed bank instructions using an established contact.
3. Test production evidence, not a showroom sample
ASQ explains that sampling supports inferences about a lot and that bias, imprecision and inconsistency can undermine them. A selected perfect sample is not proof of repeatable production quality.
Source: ASQ: Sampling and sampling errors
- Approve a production-representative sample against written acceptance criteria; record measurements, method, lot identity and inspector.
- Agree lot definition, random sampling method and defect categories with a qualified inspector. Passing sampling is not a guarantee that every unit is defect-free.
4. Score only suppliers that pass the gates
After mandatory checks pass, compare quality, delivery reliability and total cost with a documented scorecard. Agree weights before seeing quotations to avoid rationalising the cheapest offer.
- Use a limited pilot with agreed inspection and shipment milestones. Log defects, delays and corrective actions before increasing order volume.
Worked example
Illustrative scorecard: quality 40%, delivery 35%, total cost 25%. Scores of 4, 3 and 5 out of 5 produce 3.90 out of 5. These weights are a starting example, not an industry benchmark.