According to Philip Crosby, "conformance to requirements" is the basic definition of quality.

According to Philip Crosby's philosophy, quality is defined as "conformance to requirements," which means meeting or exceeding the expectations and specifications of the customer or end-user. This definition emphasizes the importance of preventing defects and errors in the products or services delivered, rather than relying on inspections and corrections after the fact. Crosby believed that quality should be the result of a systematic approach to improving processes, reducing variability, and measuring performance.