qc

Quality Control (QC) refers to the activities used to ensure that a product or service meets specified quality requirements. It is a component of quality management and is distinct from quality assurance; QC focuses on identifying defects in finished products through inspection and testing, while QA concerns the planning and improvement of processes to prevent defects.

In manufacturing and service delivery, QC employs methods such as statistical process control, acceptance sampling, product testing, inspection, calibration, and measurement systems analysis. Control charts, process capability indices (Cp, Cpk), and defect tracking are common tools. Standards and regulatory requirements may define acceptance criteria, sampling plans, and documentation.

In software engineering, QC is applied through testing activities designed to uncover defects and verify that software functions meet requirements. This includes functional testing, regression testing, performance testing, and user acceptance testing. QC in software is generally distinct from QA, which covers process improvements like software lifecycle practices and testing strategy.

In some countries, QC is also used as an abbreviation for Queen's Counsel, an honorific title for senior legal advocates; this usage is unrelated to quality control but shares the same acronym in certain contexts.

The concept of QC has historical roots in statistical quality control developed in the early 20th century by pioneers such as Walter A. Shewhart and later Deming, which influenced manufacturing standardization and modern quality management systems (QMS) under standards such as ISO 9001.