Statistical Process Control (SPC) is a quality management method that uses statistical techniques — primarily control charts — to monitor and detect changes in a manufacturing process in real time.

A control chart is a time-series plot of a process metric with statistically derived upper and lower limits, used to detect when a process is no longer behaving as it did historically.

Cpk is a short-term process capability index that measures how well a process fits within its specification limits, accounting for centring; values above 1.33 are typically required for a controlled process.

Ppk is a long-term process performance index that measures how well a process has actually performed against its specification limits over an extended period, using overall standard deviation rather than within-subgroup variation.

Cp is a process capability ratio that measures the spread of a process relative to its specification width, without accounting for centring; values above 1.33 indicate the process is narrow enough to fit within spec.

Measurement System Analysis (MSA) is a set of statistical methods used to quantify the variation in a measurement system itself — gauge, operator, and method — so that observed process variation can be trusted.

FMEA (Failure Mode and Effects Analysis) is a structured risk-assessment method that identifies potential failure modes in a design or process, scores each by severity × occurrence × detection, and prioritises mitigation effort.

IATF 16949 is the automotive industry's quality management system standard, published by the International Automotive Task Force as a supplement to ISO 9001, and required by most major OEMs of their direct suppliers.