At TMMi Level 5, the process areasDefect Prevention,Quality Control, andTest Process Optimizationwork together to support continuous process improvement. Specifically:

Defect Preventionfocuses on identifying and analysing common causes of defects and proposing corrective actions to prevent them from recurring. This includes submitting test improvement proposals, which helpTest Process Optimizationfine-tune the testing process through these insights​​.

WhileQuality ControlsupportsDefect Preventionthrough statistical methods and analysis, the correct relationship betweenDefect PreventionandTest Process Optimizationinvolves submitting test improvement proposals to optimise the process.