An economist has a wide scope of study and can specialize in several areas such as macroeconomics, microeconomics, statistics, among others.
At university a large part of the time of study is given in the microeconomics that studies the behavior of economic agents: consumer and firms. There are theories about the interaction between the consumer and the producer. The Theory of Production and Consumer Theory. Thus, the economist spends time understanding this relationship and producing insights of reality from these theories.