Unit 1: Introduction to quality

Quality is fitness for use (Juran) or conformance to requirements (Crosby).

• Service quality (SERVQUAL): reliability, assurance, tangibles, empathy and responsiveness (RATER).
• Need for quality: customer satisfaction and loyalty, lower costs of failure, competitiveness in global markets, safety and regulatory compliance, brand reputation.
• Aspects: quality of design (features and grade), quality of conformance (meeting specifications), quality of performance (in use).

• Quality characteristic: a measurable or observable property that defines fitness for use — dimensions, weight, strength, purity, appearance, response time.
• Variables (measured on a continuous scale) vs attributes (counted — defective or not).
• Specification: the target value and acceptable limits (tolerances) set by design — e.g., shaft diameter 25.00 ± 0.05 mm.
• Types: product, process, material and inspection specifications.

• Insight: spending on prevention lowers failure costs much more than it costs — "quality is free" (Crosby). The traditional optimum-quality model has given way to the view that zero defects is economical.

• Objectives: detect defects, prevent defective items from reaching customers, collect data for improvement, verify supplier quality, protect the firm's reputation.

• Advantages of SQC: detects problems early, reduces inspection cost, improves quality and productivity, provides objective data, builds quality consciousness.
• Limitations: needs trained staff and accurate data; detects but does not itself remove causes; assumes stable measurement; may be costly for small runs.