Problem Cause Finder Calculator

Defect volume signals

Reliable defect counts require a stable sampling window and a consistent product family. When counts are captured across the same shift pattern, the Share column exposes concentration quickly. In a typical line audit of 120 defects, the first two causes often represent 55–70% of observed nonconformities. This calculator computes each cause share and cumulative share so containment removes the most defects per hour, with less debate each week.

Risk scoring discipline

Severity, Occurrence, and Detection are scored from 1 to 10 using your internal guideline. A moderate failure mode might score 6×5×6 = 180 RPN, while a critical and hidden issue might score 9×6×8 = 432. Use examples tied to customer impact, safety, rework time, and escape risk. Consistent scoring tables across teams reduce argument and improve trend comparisons month to month.

Weighted prioritization

Weighted Score multiplies Defect Count by RPN so high-volume issues do not mask high-risk issues. For example, 30 defects at RPN 120 yields 3,600, while 12 defects at RPN 420 yields 5,040. The ranked list will elevate the second case for deeper root-cause work. If a cause has low count but extreme Severity, it still appears prominently, supporting proactive prevention.

6M category direction

Category totals summarize where investigation time should go across Man, Machine, Method, Material, Measurement, and Environment. If Method accounts for 48 defects and 14,000 weighted points, but Material accounts for 22 defects and 18,500 points, you may prioritize supplier checks despite lower volume. Use the category view to allocate engineering, maintenance, and quality resources without losing sight of process capability.

Verification planning

After countermeasures, re-sample the same product family and compare pre/post totals. Many teams target a 30% reduction within two weeks, then a 60% reduction within eight weeks, while monitoring customer complaints. Update Detection scores as poka-yokes, gauges, or checklists are deployed. If Occurrence remains high, escalate to design of experiments or preventive maintenance adjustments.

Communication and traceability

Exported CSV and PDF outputs make reviews faster and keep action lists aligned. Share the top three causes, their RPNs, and the Pareto cutoff in daily tier meetings. Capture owners, due dates, and verification evidence so fixes are sustained. When the same cause returns, compare the previous RPN and detection controls to identify drift, training gaps, or measurement instability.

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FAQs

1) What does the Pareto flag mean?
It marks whether a cause falls within the first 80% of total defects, based on the ranked list. Use it to focus on the vital few before spending time on low-impact causes.

2) How should we score Detection?
Use higher numbers when a defect is hard to catch before shipment. If an automated inspection reliably catches it, use a lower score. Keep the scale consistent across teams.

3) Why use Weighted Score instead of count only?
Count alone misses risk. Weighted Score combines volume and RPN, so a less frequent but severe and hard-to-detect issue can rise to the top.

4) Can we compare results between weeks?
Yes, if the sampling window, product mix, and scoring rules stay consistent. Track total defects, top cause changes, and category totals. Re-score Detection when controls improve.

5) What if two causes have the same score?
The calculator breaks ties using defect count, then preserves order. In practice, treat tied items as a cluster and validate with additional data, observations, or a focused audit.

6) Which causes should get a 5-Why first?
Start with the top weighted causes and any items still within the 80% cumulative share. Then include any cause with very high Severity even if its count is smaller.