Gate reviews are milestones that play an important role, especially in Six Sigma projects. They are used to evaluate results generated during a specific phase and ensure well-founded project progress. The project team presents the phase-specific work results to the sponsor, who acts as the project client. If all agreed (sub-)goals have been achieved, the sponsor approves the phase completion, giving the “GO” for entering the next phase; if not, improvements must be made. Gate review meetings take place when the end of a phase, such as the DMAIC roadmap, is approaching. In a Six Sigma project, at least five Gate reviews must be organized.