A social exchange framework "refers to any conceptual model or theoretical approach that focuses on the exchange of resources (material or symbolic) between or among people". Social exchange theories expand the concepts of economics to "the notion of exchange to include all interpersonal experiences". Social exchange theories comprise falsifiable propositions: propositions can be found false. Thus, this group of theories is considered to be post-positivist. Communication is the means through which an exchange is negotiated and conducted. Much more interesting, however, is the idea that the communication itself can serve as the resource that is exchanged either directly or symbolically. Interdependence theory centers on expectations, comparisons, and alternatives. Individuals make two types of comparisons in evaluating a relationship. The comparison level (CL) is the amount of rewards one thinks one should receive. Social exchange theories are post-positivistic theories and therefore propositions should be able to be tested.