Supplier selection matrix: weighted criteria and knock-outs

Why a matrix

Supplier selection usually ends as a price discussion. A weighted matrix puts quality, capability, capacity and risk on the same page as price, so the decision is made on facts and documented for the auditor (IATF 16949 clause 8.4.1.2 asks for a documented supplier selection process with a risk assessment).

Criteria and weights

Score from data, not opinion

Score 1 (poor) to 5 (excellent). Where data exist, derive the score instead of guessing: capacity from free capacity vs the required rate, capability from the lowest Cpk of the key characteristics, risk from a weighted risk index, price from the quote ranking. Leave a criterion blank when it is not assessed and report the assessment coverage, so a candidate with half the data does not win by accident.

Knock-outs

• A score of 1 on a knock-out criterion rejects the candidate, whatever the total.
• Typical knock-outs: no valid IATF certificate at SOP, capacity utilization above 100 %, Cpk below 1.00 on a special characteristic, high supply risk without a mitigation.
• Knock-outs stop a cheap but incapable supplier from winning on price.

Capacity check

Required weekly rate = annual volume ÷ working weeks × peak factor × (1 + safety margin), for example 120,000 ÷ 48 × 1.15 × 1.15 = 3,306 parts per week. Compare it with the candidate’s free capacity (capacity per week minus what is committed to other customers). Up to 85 % utilization is OK, 85–100 % is tight and needs a capacity plan, above 100 % is not OK. Confirm with a Run@Rate on the real process.

Worked example

Decision rules

• Approve from 75 %, approve with conditions from 60 %, below that reject.
• Conditions are written with owner and date (for example capacity plan for a second press, Cpk ≥ 1.67 at PPAP).
• The sourcing board signs the decision; after nomination the supplier moves to the monthly scorecard.