DMAIC is Six Sigma’s project model in five phases: Define (bound the problem), Measure (measure current performance), Analyze (find root causes with data), Improve (implement and verify solutions) and Control (sustain the gain with management).
DMAIC suits complex problems where the cause is not obvious and where data must separate assumptions from facts — typically quality and variation problems. For simple, visible problems, A3 or kaizen is faster.
The Control phase is the most frequently neglected: without standards, training and ongoing measurement, the process slides back, and the gain evaporates within months.