Distinguish between researchable and non-researchable questions
A researchable research question is one that can generate a hypothesis that can be tested through a structured and rigorous process of data collection, analysis and testing, either quantitatively, or qualitatively or a hybrid of methods.
A non-researchable research question is, therefore, one that is not formulated to enable a testable hypothesis to be generated. This does not mean that the topic is not capable of sustaining research. Often it is a matter of recasting the question so that specific testable hypotheses can be formulated.
Non-researchable questions could be too broad or vague, or they could be questions for which answers are easily obtainable.
In short Researchable problems imply the possibility of empirical investigation. Non-researchable problems include explanations of how to do something, vague propositions, and value-based concerns.