When analyzing consumer behavior, we’re talking about people trying to get satisfaction—that is, about subjective feelings. Yet there is no simple way to measure subjective feelings. How much satisfaction do I get from my third fried clam? Is it less or more than yours? Does it even make sense to ask the question?

Luckily, we don’t need to make comparisons between your feelings and mine. All that is required to analyze consumer behavior is to suppose that each individual is trying to maximize some personal measure of the satisfaction gained from consumption of goods and services. That measure is known as the consumer’s utility, a concept we use to understand behavior but don’t expect to measure in practice. Nonetheless, we’ll see that the assumption that consumers maximize utility helps us think clearly about consumer choice.