Table 2.

Ontological assumptions of positivism, post-positivism, constructivism/interpretivism, and critical theory [30, 33–39]

Paradigm	Positivist	Post-positivist	Constructivist/interpretivist	Critical theory
Ontological assumptions	There is a single, objective reality that can be observed through science.	There is a single, objective reality. However, scientific observations involve error so reality can only be known imperfectly.	There are multiple subjective realities, each of which is socially constructed by and between individuals.	There are multiple subjective realities influenced by power relations in society. Reality is shaped by social, political, cultural, economic, ethnic, and gender values.