A Critical to Quality Tree (CTQ Tree) is a tool that turns customer needs into specific, measurable, and actionable performance requirements.
The Plan Do Check Act Cycle, aka A Deming wheel, Shewhart wheel or Shewhart Cycle is the foundation of continuous improvement frameworks
A SIPOC (Supplier, Input, Process, Output, and Customer) is a high-level process mapping tool to help visualize a process and its influences.
An affinity diagram helps organize ideas into meaningful categories. This makes analysis on large data sets easier.
Quality Function Deployment (QFD) and House of Quality (HOQ) is a structured approach for defining customer requirements.