Which phase of Six Sigma involves specifying the boundaries of a project?

The Control phase focuses on maintaining the improvements made during the project and ensuring that processes remain within specified limits. It is concerned with monitoring the performance of the improved processes rather than defining the project's boundaries or objectives.

The Measure phase involves collecting data and establishing baseline performance metrics to understand the current state of the process. While it is critical for assessing performance, it does not include specifying the project's scope or boundaries, which is specifically addressed in the Define phase.

The Improve phase is where solutions to address the identified problems are developed and implemented. It focuses on enhancing processes and outcomes but does not involve setting the initial boundaries or objectives of the project, which is done in the Define phase.