Methodological gap: Addresses the conflict with the research methods in the prior studies and offers a new line of research that is different from those research methods
Theoretical gap: Deals with the gaps between theory and early research
Population gap: Relates the population that is not adequately represented or under-researched in the evidence base or prior research
Evidence gap: Deals with research findings contradiction
Empirical gap: Addresses conflicts that no study, to date, has directly attempted to evaluate a subject or topic from an empirical approach
Practical-knowledge gap: Arises when the actual behavior in practice is different from the expected behavior. In this case, research could seek to determine the scope of the conflict and to uncover the reasons for its existence
