You can begin the integration of six sigma with project planning with the development of a project life cycle. By doing this, you can add statistical knowledge of the problem, reduce the chance of an incorrect assessment of the issue and reduce the bias that influences perceptions about a particular problem.

Six sigma can also be used for measurement of the problem in the validation phase of the life cycle using gage R&R, FMEA, and control plans.

“The tools of both project management and Six Sigma can be placed in this life cycle to plan, act, do and check for a process improvement project.”

By using six sigma tools, there exist a series of troubleshooting tools and methodology to the project management system. The integration of six sigma can be used for both transactional and manufacturing organizations during the project planning process.

https://www.isixsigma.com/methodology/project-management/integrating-project-management-six-sigma-system/