Example Data
| Case | Sample | Defects (C/M/m) | Compliance (%) (Doc/Pack/Trace/Cond) | OTD (%) | Response (days) | Cert | Overall | Grade | Decision |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 125 | 0 / 2 / 6 | 96 / 94 / 95 / 98 | 98 | 4 | ISO 9001 | 90.69 | A | Accept |
| 2 | 80 | 0 / 5 / 12 | 85 / 80 / 78 / 88 | 90 | 14 | None | 66.20 | D | Reject |
| 3 | 50 | 1 / 0 / 2 | 92 / 90 / 90 / 94 | 96 | 3 | IATF 16949 | 84.02 | B | Reject (critical) |
Formula Used
1) Penalty points
Penalty Points = (Critical × Critical Points) + (Major × Major Points) + (Minor × Minor Points)
2) Penalty per 100 units
Penalty per 100 Units = (Penalty Points ÷ Sample Size) × 100
3) Defect score
Defect Score = max(0, 100 − Penalty per 100 Units)
4) Compliance score
Compliance Score = average(Documentation %, Packaging %, Traceability %, Delivery Condition %)
5) Delivery & supplier score
Delivery Score = (0.60 × OTD %) + (0.25 × Response Score) + (0.15 × Certification Score)
6) Overall incoming audit score
Overall Score = (Defect Score × Defect Weight) + (Compliance Score × Compliance Weight) + (Delivery Score × Delivery Weight)
Weights are converted to fractions and auto-normalized so they total 100.
How to Use This Calculator
- Inspect an incoming lot using your sampling plan and record the sample size.
- Count critical, major, and minor defects observed in the sample.
- Fill the compliance percentages based on your receiving checklist results.
- Enter service metrics: on-time delivery, response time, and certification level.
- Adjust weights if your program prioritizes defects, paperwork, or service differently.
- Click Calculate Score to view the score and decision above.
- Use Download CSV or Download PDF to save the report.
Why Incoming Audit Scores Matter
Incoming inspections protect production schedules and customer safety. A score converts mixed findings into a repeatable decision that can be trended weekly. When lots are scored on the same 0–100 scale, managers can rank suppliers, highlight chronic issues, and justify containment costs. Many teams set an “accept” band above 90, a “conditional” band from 75 to 89, and escalate anything below 75 for review. Pair the score with photos, lot IDs, and NCR numbers for faster audits.
Balancing Defects With Compliance
Defects drive direct quality loss, while compliance reveals process discipline. The calculator converts defect counts into penalty points and then into a defect score, so a larger sample reduces volatility. Compliance is averaged across documentation, packaging, traceability, and delivery condition. If paperwork is weak but defects are low, increasing the compliance weight from 30 to 40 can prevent risky releases and encourage corrective actions.
Using PPM and DPU to Compare Lots
Defects per million (PPM) and defects per unit (DPU) normalize results across different sample sizes. For example, 8 total defects in 125 units equals 64,000 PPM and 0.0640 DPU. A second lot with 3 defects in 50 units equals 60,000 PPM and 0.0600 DPU, which is slightly better despite fewer inspected units. Tracking PPM alongside the score helps separate true improvement from sampling noise.
Supplier Service Factors That Shift Risk
Delivery performance changes the cost of a defect. The delivery component blends on‑time delivery, responsiveness, and certification. A supplier at 98% OTD, 4‑day response, and ISO controls typically scores above 90 on this sub‑metric. If response stretches past 10 days, the responsiveness score drops sharply, signaling that future escapes may linger longer in your system and increase line‑stop probability.
Setting Thresholds and Continuous Improvement
Use the weights to match your product risk. Safety‑critical parts often use defect weight near 60 with automatic rejection for any critical defect. High‑mix, low‑volume programs may raise the delivery weight to prioritize reliability. Review monthly averages, investigate the top three flags, and require action plans tied to measurable targets, such as reducing major defects by 30% and raising traceability to 95% within one quarter.
FAQs
How should I choose the sample size?
Use your approved sampling plan or customer requirement. Larger samples reduce volatility and make PPM trends more reliable. If you inspect fewer units, treat the score as an early signal and confirm with additional sampling before final release.
How do defect points change the score?
Points convert defect counts into penalty severity. Increasing critical or major points lowers the defect score faster, which reduces the overall score when defect weight is high. Keep points consistent across suppliers so comparisons remain fair.
Why does a single critical defect trigger rejection?
Critical defects often imply safety, legality, or functional failure risk. Many receiving procedures require immediate rejection or quarantine to prevent escapes. If your process allows conditional release, change the rule in the decision logic section.
Should I adjust the default weights?
Yes, when your risk profile differs. Defect-heavy programs may raise defect weight, while regulated documentation may raise compliance weight. Normalize weights to 100 and keep them stable for a quarter to evaluate improvement objectively.
What does “Conditional” mean in practice?
It suggests controlled use with containment actions. Typical steps include quarantine, 100% screening, deviation approval, and corrective action requests. Use the flags and sub-scores to focus on the biggest driver behind the reduced score.
How can I use exports effectively?
Download CSV for quick trending in spreadsheets and PDF for audit evidence. Store the report with lot numbers, inspection photos, and nonconformance references. This creates a traceable record for supplier reviews and internal quality meetings.