Realist and the social constructionist are both taken as ontology by post positivist researchers in communication discipline. That is, it can be true that post positivist researchers believe that there is an empirical, unchallengeable reality independent of our perceptions, but limitations like the complexity of the reality and the biases of researchers still exist which causes our incomplete understanding of the reality. Even though, by applying the mutiple measures and observation, post positivist believe researchers can enhance the objectivity and attain a more and more fully apprehended reality. At the same time, post positivists also have faith in multiple realities which can be constructed by social collectives through communicative interaction in relatively patterned ways and its effects should be regular and predictable which in turn reified social constructions. Thus, post positivists study regularities and patterns.
Post positivist researchers in communication base their assumptions largely on the so-termed modified objectivist which holds to the notion that causal relationships for regularities observed in the social world is the center of the search for knowledge.(Textbook, chpt3) Nevertheless, post positivists largely reject the value-free inquiry and the absolute authority of scientific method. Instead, post positivists believe that with careful and systematic operations as well as awareness of values, scholars can strive to be as unbiased as possible "by using controls and statistical tests, insisting on replication, and so forth." (Textbook, chpt3) Therefore, post positivism does not equal to qualitative