Kano categorizes the attributes of a product into three classes:

  1. Must-be attributes: Represents basic musts or functions expected of a product or service. When present they are neutral, when absent they dissatisfy consumers.
  2. Performance attributes: Directly linked to voiced demands of customers. Relative to quality and their willingness to pay. Enhances satisfaction.
  3. Surprise and delight factors: These factors excite the customer and satisfy a latent need. Their presence increases satisfaction, their absence does not decrease it. Source of differentiation.