The Kano model is a technique used to support decisions regarding which features should be included in a product or service. There are a number of variants of this technique available, but generally the following categories are included. Must-be qualities: The attributes that are expected from a product or service. Their presence does not necessarily improve customer satisfaction, but their absence negatively impacts upon customer satisfaction. One-dimensional qualities: This category describes qualities that increase satisfaction when included, but decrease satisfaction when excluded. Attractive qualities: These attributes provide satisfaction when they are included, but not cause dissatisfaction when they are not present. Indifferent qualities: Provoke neither a positive nor negative reaction. Reverse qualities: Can cause dissatisfaction for some customers, but satisfaction for others.