Operations & Quality Economics Lab

Cost of Quality (COQ) & Defect Lab

Calculate total Cost of Quality (COQ) across the PAF framework: Prevention, Appraisal, Internal Failure, and External Failure. Model the ROI of mistake-proofing and defect prevention.

COQ Model Prevention ROI Simulator Quality Theory & Formulas FAQ

Industry Quality Presets

Load calibrated quality cost and failure profiles.

Step 1: Revenue & PAF Quality Costs

PAF Framework Quality Cost Inputs

$
Top-line business sales for the annual period.
Total output volume across the year.

Cost of Conformance (Good Quality)

$
Staff training, poka-yoke error-proofing, supplier quality audits, process standardization.
$
Inspections, automated QA tests, audits, sensor calibrations, mystery shoppers.

Cost of Non-Conformance (Poor Quality Waste)

$
Scrap, discarded food/materials, rework, assembly line stoppage downtime, reinspection.
$
Customer returns, warranty repairs, comped meals, support escalations, churn.
Total Quality Cost
$0
COQ % of Revenue
0.0%
Cost of Conformance
$0
Failure Waste (CONC)
$0
Quality Cost / Unit
$0.00
Conformance Balance
0.0x

PAF Cost Category Breakdown

Quality Cost Category Annual Cost ($) Share of Total COQ Classification & Impact

Step 2: 1-10-100 Quality Economics

Prevention Investment & Failure Reduction ROI

Simulates the classic 1-10-100 rule: investing in root-cause error-proofing eliminates compounding scrap, customer returns, and churn.

Prevention Investment Plan Internal Scrap Savings External Return Savings Net Annual Profit Lift & ROI

Quality Economics Guide

Understanding the economics of quality

Total Quality Management (TQM) establishes that preventing defects at the design and process level is vastly cheaper than inspecting or fixing them downstream.

  • The 1-10-100 Rule: Preventing a defect costs $1. Finding and fixing it internally in inspection costs $10. Letting it escape to a customer costs $100+.
  • Hidden Factory: Rework and scrap create an invisible second operation that consumes labor, equipment, and cash without creating revenue.
  • Optimal COQ Zone: World-class operations aim for a 3:1 ratio of Conformance investment to Failure waste.

Test kitchen and waste dynamics in the Restaurant Simulator and Coffee Shop Simulator.

COQ Equations

Quality cost formulas

Total Cost of Quality (COQ) = Prevention + Appraisal + Internal Failure + External Failure

Cost of Conformance (COC) = Prevention + Appraisal

Cost of Non-Conformance (CONC) = Internal Failure + External Failure

COQ % of Sales = (Total COQ ÷ Total Annual Revenue) × 100

Quality Cost Per Unit = Total COQ ÷ Total Units Produced

Explore process constraints in the Childcare Simulator or Hair Salon Simulator.

FAQ

Cost of quality questions

What is the Cost of Quality (COQ) PAF model?

The PAF model divides quality costs into four categories: Prevention (training, mistake-proofing), Appraisal (testing, inspection), Internal Failure (scrap, rework before delivery), and External Failure (returns, warranty, customer churn).

What is the difference between Conformance and Non-Conformance?

Cost of Conformance (COC) is the proactive cost of ensuring quality (Prevention + Appraisal). Cost of Non-Conformance (CONC) is the reactive waste caused by defects (Internal + External Failure).

What is the 1-10-100 Quality Rule?

The 1-10-100 rule states that spending $1 on Prevention saves $10 in Appraisal/Rework costs and $100 in External Failure costs, lost customers, and brand damage.

What is a typical healthy Cost of Quality as a percentage of sales?

In benchmark organizations, total COQ is typically 5% to 10% of revenue, with a dominant share invested in Prevention. Unmanaged organizations often waste 15% to 25% of sales on failures.

Can I export Cost of Quality models to CSV?

Yes. You can export the complete PAF breakdown and prevention ROI simulation as a UTF-8 CSV spreadsheet with formula injection defense or print a management report.

Are these calculations formal Six Sigma or ISO certification audits?

No. This tool provides educational models for operations management practice without formal ISO 9001 registrar auditing or certified Six Sigma Black Belt verification.

Continue Exploring Operations Tools

Explore our Operations & Quality Simulation Games Hub, model labor productivity in the Staffing Capacity Simulator, analyze inventory flow in the Cash Conversion Cycle Simulator, or test contribution margins in the Break-Even Matrix Lab.