Theory, Construct, Concept: Hierarchy of Knowledge

Theory refers to a set of propositions to explain or guide social actions.
In inductive research strategy, to establish a theory from empirical data is the goal.
On the other hand, deductive research strategy will mainly test hypotheses that are derived from existing theories.
To research is, by the way, motivated some aspiration to find out reality.
This aspiration will vary according to what the researcher wishes to find out.
In this sense, this aspiration may determine objectives of a research.
Hence, objectives of a research also vary.
In some occasion, a researcher may be interested in describing what is going on in a certain societal circumstance. In other, objectives may contain subsequent action based on what will have been identified as a result of the research.
Despite the variety of those objectives of or motivation towards research, it should be entailed by some abstraction from data.
In the terminology of research, there is a hierarchy of the abstraction.
Concepts will be defined by each researcher, and they will form a building block of his/her knowledge claims, which will be generated through research activities. In other words, concepts would be regarded as assumptions for the research.
Constructs will be derived from analyses of data in the course of the research.
They need to be based on concepts defined prior to those analyses of data. So, constructs may be seen as something derived from abstraction of related concepts in the same research.
Theories would be further abstracted general rules, institutions, or systems, which will explain outcomes of the research.
Those theories are said to be continually created by human beings. And, they will be utilised in defining concepts of other research. (Of course, roles of theory are not limited to this at all. Some of them may immediately be followed by concrete interventions. In this sense, theories are utilised as foundations for making decision on policies, programmes, or projects in order to provide solutions for certain social problems.)