The three TMMi level 5 process areas.

At TMMi Level 5, the process areas Defect Prevention, Quality Control, and Test Process Optimization work together to support continuous process improvement. Specifically:

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

While Quality Control supports Defect Prevention through statistical methods and analysis, the correct relationship between Defect Prevention and Test Process Optimization involves submitting test improvement proposals to optimise the process.