01 · The Question
No Review Exists in Your Country, but Is That Really a Gap?
You search the literature and discover several systematic reviews addressing your question. They appear relevant, but none focuses specifically on your country.
That can produce an appealing rationale: “No systematic review has examined this topic in the Philippines,” “No review has synthesized evidence from Brazil,” or “No country-specific review exists in Kenya.” The statement may be factually correct. The harder question is whether it identifies a meaningful research gap.
Countries can differ in institutions, resources, policies, cultures, populations, infrastructure, implementation conditions, and many other characteristics capable of affecting research findings. But a national border does not automatically make evidence on one side scientifically different from evidence on the other.
The review needs a reason why place matters to the question, not merely proof that nobody has published the country-specific version yet.
03 · What You Need to Know
When Geography Becomes a Meaningful Review Boundary
“No review in my country” establishes absence, not importance
Finding no country-specific review answers one question: has somebody published a review restricted to this country?
It does not answer the more important question: would restricting the evidence to this country improve what researchers or decision-makers know?
PRISMA 2020 asks review authors to describe their rationale in the context of existing knowledge and, when similar systematic reviews already exist, explain why another review is necessary. Legitimate reasons can include outdated or discordant reviews, methodological problems, newer review methods, or a review commissioned to inform a particular policy or guideline. A geographic restriction therefore needs to be situated within a substantive rationale rather than treated as self-evident novelty.
Ask what the country boundary represents scientifically
Country is often a proxy for other characteristics.
A health intervention may operate within a different financing or delivery system. An educational technology may encounter different infrastructure, curricula, assessment practices, language conditions, institutional policies, or patterns of access. A workplace intervention may interact with different labor structures or regulatory environments.
Cochrane's guidance on equity and specific populations emphasizes that research occurs within social, cultural, political, geographical, and organizational contexts that may influence intervention effectiveness and implementation. It recommends considering why findings should or should not apply to the population and context of interest.
A strong country-specific rationale therefore identifies the contextual characteristic that matters.
Geographic novelty
No review has previously restricted its evidence to this country.
Contextual justification
Features associated with the country could plausibly affect the evidence, its applicability, implementation, outcomes, or interpretation.
The first makes the proposed review different. The second can make it useful.
Existing international reviews may already contain your country's evidence
A review does not need your country's name in its title to include evidence from that country.
Inspect the characteristics and locations of included studies. An international systematic review may already contain several local studies, and it may even examine geography through subgroup or contextual analysis.
If so, the question becomes whether the existing review already provides the answer you need. Extracting the same local studies and publishing them as a separate country-specific review may contribute little if the international synthesis already addresses their applicability adequately.
Evidence from elsewhere is not automatically irrelevant
The opposite mistake is assuming that evidence generated outside your country cannot inform decisions within it.
External evidence may remain highly applicable when the mechanisms, populations, interventions, and implementation conditions are sufficiently comparable. Country-specific evidence may also be sparse, making broader evidence particularly informative.
Cochrane's discussion of low- and middle-income countries illustrates the principle well. Restricting a review geographically can be appropriate when there are compelling reasons to expect the problem, intervention, outcomes, or functioning of the intervention to differ. Geographic status by itself is not necessarily sufficient.
The same reasoning extends beyond healthcare. The relevant issue is transferability, not the passport of the dataset.
Context can change absolute effects even when relative effects are similar
Country differences do not always imply that an intervention's underlying relative effect changes.
Baseline conditions may differ instead. Different prevalence, resources, infrastructure, access, or implementation conditions can change the absolute consequences of an intervention even when relative effects are reasonably transferable.
This matters because a country-specific synthesis may sometimes be useful for decision-making even without a strong hypothesis that the basic causal effect differs. The rationale should explain what contextual information the local evidence contributes.
Country-specific evidence may address implementation rather than effectiveness
A global review may establish that an intervention can work while leaving local implementation questions unresolved.
For example, an educational technology might show broadly favorable outcomes internationally, yet adoption within a particular national system could depend on internet access, institutional procurement, teacher preparation, language, assessment policy, or data governance.
In such a case, the unresolved question may not be “Does the intervention work in this country?” It may concern implementation, acceptability, feasibility, barriers, or contextual adaptation.
That distinction should shape the review question and the type of evidence synthesized. Forcing a local effectiveness review onto what is really an implementation problem can produce an oddly shaped review and, eventually, an equally oddly shaped discussion section.
Check whether enough country-specific primary evidence exists
A country-specific gap can be conceptually important but empirically unreviewable.
Before restricting the review, search for eligible primary studies from the country. Determine how many exist, what questions they address, which designs they use, and whether their data can meaningfully be synthesized.
Cochrane warns that review authors should consider whether a proposed question is answerable using existing evidence because an excessively narrow scope may produce an empty review.
If only one or two highly heterogeneous studies exist, a narrowly restricted systematic review may add less than a broader synthesis that explicitly evaluates applicability to the country.
Do not confuse where the authors live with where the evidence comes from
A review conducted by researchers in your country is not necessarily a country-specific review. Likewise, a review conducted elsewhere may synthesize substantial evidence from your country.
What matters is the evidence and question, not the institutional affiliation of the review authors.
“No researcher from our country has reviewed this” is therefore usually a weak scientific rationale unless local involvement itself is relevant to the review's purpose, such as stakeholder-informed evidence synthesis for a national policy process.
A national policy need can create a legitimate rationale
Sometimes the intended use of the evidence makes a country-specific synthesis valuable.
PRISMA 2020 explicitly recognizes that a systematic review may be commissioned to inform a guideline or policy for a particular organization. Similarly, a national agency may require synthesis tailored to its population, systems, regulatory environment, or implementation constraints.
In such cases, the rationale is not simply “there is no review from this country.” It is that a defined decision requires evidence assessed for applicability to that jurisdiction.
Country restrictions can conceal relevant regional evidence
National boundaries can sometimes be too narrow for the underlying question.
Neighboring or comparable countries may share relevant educational systems, resource constraints, epidemiological patterns, institutional structures, languages, or implementation conditions. Excluding all such evidence solely because it lies outside a political border can reduce the information available without improving applicability.
A regional or context-based eligibility criterion may sometimes be more defensible than a country criterion.
Country differences are one form of a broader population question
Geographic distinctions overlap with the broader problem of deciding whether different populations justify another review.
In both cases, the same principle applies: identify the characteristic that could change the answer. Geography becomes scientifically informative through the contextual differences it represents.
A manufactured country gap can become unnecessary duplication
If a rigorous, current international review already contains the relevant local evidence and its findings are reasonably applicable, repeating the synthesis with a country filter may simply reduce the dataset.
The proposed review can be technically unique while adding almost no information. When the main contribution is “this has never been done using only studies from Country X,” ask whether that distinction actually reduces uncertainty.
If it does not, the project may move closer to review duplication that consumes resources without producing a useful additional answer.
