What a research gap is
A research gap is not a dramatic statement that a topic has never been studied. It is a bounded account of what available evidence does not yet establish. The gap may concern a population, setting, mechanism, measure, method, time period, inconsistency, or unanswered comparison. It should lead directly to a question the present study can address.
Build the claim from the literature review. Record the search scope, distinguish missing evidence from mixed evidence, and cite the studies that define the boundary. If the search was narrow, describe it as narrow.
Patterns for specific gaps
Although [established finding] has been documented in [studied context], evidence regarding [specific unresolved issue] remains limited in [target context].
Studies differ in their estimates of [relation], leaving the role of [specific source of uncertainty] unresolved.
The first pattern fits a coverage gap. The second fits inconsistent findings. Replace every bracket with facts supported by the review and preserve any uncertainty in the cited literature.
Connect the gap to the study
After stating the gap, explain why resolving it matters and how the research aim responds. Do not claim importance through generic language. Name the scientific, theoretical, methodological, clinical, or policy decision affected by the uncertainty. Then state an aim whose design, sample, and measures can actually address the stated issue.
Search the Phrase Explorer for additional patterns and inspect their evidence requirements.