Defining the Voice of the Customer (VOC) includes what the customers’ requirements are for products and services and what their expectations are: both positive and negative, including likes, dislikes, problems, and suggestions.
It helps determine core business processes involved in their needs and helps the project team develop the Critical to Quality elements (CTQs) and develop key process metrics (KPOVs). The VOC asks what each customer desires; specifically, what is important to them, and what do they perceive is a defect in a quality or service.