Economists borrow from all the social sciences in order to theorize about human behavior.
They borrow from mathematics in order to express theories concisely. And, finally, they borrow from statistics in order to make inferences from real-world data about hypothesis suggested by economic theory. Economists are interested in understanding human behavior not only for its own sake, but also because of the policy implications of this knowledge. As in other scientific disciplines, theory in economics is an abstraction, or simplification, of innumerable complex relationships in the real world. When thinking about some aspects of behavior, economists will build a model that attempts to explain the behavior under examination.