Customer satisfaction refers to an individual’s subjectively derived favourable evaluation of any outcome and/or experience associated with consuming a product. In specific, satisfaction is the outcome of a post-purchase evaluation, and comparison with priori expectations, of rewards and costs.

Mathematically, customer satisfaction equates the net value, or satisfaction with the product, S(t) at time t to the difference between the cumulative realized value V(t) at time t and the purchase price P of the product (hence, S(t) = V(t) – P).

The highest level of satisfying customer expectations is reached then when the customer gets more from a product than originally expected.

Satisfaction, however, is but one component in determining long-term customer retention.  The construct of customer loyalty is comprised of behaviour-based metrics, such as "likelihood to recommend a product or service to others" and/or "likelihood to repurchase the product or service," and attitude-based metrics such as "overall satisfaction."

Statistical Reasoning takes it one step further by incorporating the role of evaluating brand commitment, trust, and affect for a truly holistic and inclusive approach to customer loyalty measurement.