Capturing Requirements

Quality is conformity to requirements, so quality planning begins with knowing what they are. Three categories must be captured.

• Stated requirements — what the customer specified in the order, drawing or contract.
• Implied requirements — necessary for the intended use even though unstated. A customer ordering a pressure vessel does not specify that it should not leak.
• Statutory and regulatory requirements — applicable regardless of what the customer asked for, and not waivable by agreement.

Reviewing before commitment

Requirements must be reviewed before agreeing to supply, checking that they are understood, achievable with the available process and capacity, unambiguous, and that any differences from a previous order are identified. Accepting an order you cannot meet is a quality failure at the first step, and it is the most expensive one to discover later.

Making requirements measurable

A requirement that cannot be measured cannot be controlled. "Good surface finish" must become a roughness value and a measurement method; "delivered promptly" must become a date and a definition of delivery. Ambiguity in the specification becomes a dispute at inspection, invariably at the worst moment.

Every characteristic on a drawing is an instruction to measure something. If you would not inspect it, ask why it is specified; if you would, ask how.