Cost of Quality in Project Management

Understanding Cost of Quality

Evaluating the cost of quality ensures a project balances the expenses of achieving quality with the costs of quality failures. It involves four categories: Prevention, Appraisal, Internal Failure, and External Failure.

• Prevention: Costs to prevent quality issues, including planning and system implementation.
• Appraisal: Costs for monitoring and controlling quality, such as audits, verification, and validation.
• Internal Failure: Costs from issues found before reaching the customer, like waste, scrap, and rework.
• External Failure: Costliest issues occurring after delivery, impacting reputation and finances (e.g., defective touchscreen technology for truck drivers).

Marginal Analysis

Cost of quality is planned, monitored, and measured throughout the project. Marginal analysis identifies when the benefits of improving quality equal the costs, stopping further quality enhancements when added value diminishes.

Logical Data Models

A data model represents data types and their relationships in an application. For example, an Entity Relationship Diagram (ERD) shows how "office location" relates to "worker," with a business rule that a worker may not need an office assignment.

Mind Mapping

Mind maps diagram ideas to generate, classify, or record information, aiding in gathering quality requirements and showing their impact on project planning.

Matrix Representations

Matrices display relationships between sets of items in rows and columns. For quality planning, they list requirements and characteristics (e.g., priority levels). Agile backlogs are an example. A prioritization matrix (Figure 10.4) ranks options numerically, suggesting the top two choices but limiting unit tests to three iterations.

Flowcharts

Flowcharts (process maps) illustrate process flows, interrelations, and alternative paths. They help define processes, identify dependencies, and uncover quality issues by studying defective steps.

Test and Inspection Planning

Quality planning includes determining how to confirm deliverables meet quality standards and evaluating performance and reliability. Testing methods vary by project type, and the quality management plan prevents issues.

Methods for Managing Quality

Checklists

Checklists (Figure 10.6) confirm process steps, analyze defects, and assess deliverables against acceptance criteria.

Cause-and-Effect Diagrams

Cause-and-effect (Fishbone/Ishikawa) diagrams (Figure 10.7) verify policy adherence and procedure adequacy for quality deliverables.

Scatter Diagrams

Scatter diagrams (Figure 10.8) track two variables to analyze their relationship to quality, using regression lines for forecasting (e.g., paint quantity vs. drying time).

Histograms

Histograms (Figure 10.9) analyze defect types and frequencies to focus quality improvements.

Document Analysis

Document analysis reviews testing results to identify deficiencies in the quality management plan and processes.