01 · The Question
When does a local question require a regional database?
Suppose your study concerns maternal health in Latin America, teacher professional development in Southeast Asia, agricultural practices in a particular country, or another geographically bounded question. You already have access to major international databases. Do you also need to search databases that specifically cover the country or region?
Potentially, yes. National and regional databases may index journals and other literature that broader international databases do not cover. But adding a regional database simply because your research has a geographic label is not automatically useful. The real issue is whether it gives you access to relevant evidence that your existing sources may miss.
02 · The Short Answer
Search regionally when the evidence is likely to be regional
In Brief
You should consider searching regional or national databases when your research question depends substantially on evidence from a particular place and relevant local literature may not be adequately represented in the international databases you are already searching.
Regional databases usually complement rather than automatically replace major disciplinary or multidisciplinary databases. Their value depends on their subject scope, geographic coverage, languages, indexed sources, search functionality, and how much distinctive relevant evidence they contribute.
03 · What You Need to Know
Regional databases can expose a different part of the evidence base
Regional databases exist because scholarly literature is distributed unevenly
Research produced in a country or region does not necessarily flow through the same publication channels as research elsewhere. Some studies appear in journals covered by large international databases. Others are published in regional or national journals and scholarly networks with more limited international indexing.
Information-retrieval guidance for systematic reviews recognizes this issue. The Campbell Collaboration's guidance notes that many countries and regions maintain databases concentrating on literature produced in those areas and that these resources often contain journals and other literature not indexed elsewhere.
This is one reason a conventional search can underrepresent research from particular countries even when the search itself is carefully constructed.
Geography must actually matter to the question
A regional database becomes especially relevant when the population, setting, policy system, intervention, institution, environment, or phenomenon being studied is geographically bounded.
Imagine a review of national policies governing artificial intelligence in higher education. Local regulations, institutional arrangements, educational terminology, and implementation conditions may make country-specific literature substantively important. A regional or national source that reaches that literature could therefore add something your international database does not.
Contrast that with a review of a laboratory measurement technique for which geography has little theoretical or practical bearing on the phenomenon. A regional database might still contain relevant studies, but the geographic dimension alone gives you much less reason to prioritize it.
Geographically located research
A study happened to be conducted in a particular place, but location is not central to the question being answered.
Geographically dependent research
The local population, system, environment, policy, culture, language, or institutional context is part of what makes the evidence relevant.
The second situation generally creates a stronger methodological case for searching regionally.
Regional databases can retrieve unique studies
The potential contribution is empirical rather than merely hypothetical. In a methodological analysis of a World Health Organization systematic review of maternal morbidity and mortality, researchers compared records identified through multiple databases. Among electronically identified included citations, 5.6% were found uniquely through LILACS, the Latin American and Caribbean Health Sciences Literature database. The authors concluded that searches for this particular evidence base needed to extend beyond well-known electronic databases to regional and other relevant sources.
That percentage should not be treated as a general estimate of what a regional database will add to your own review. Other studies have found different contributions, including little or no unique yield from particular regional databases for particular topics. Database value is conditional on the question.
This is precisely why counting databases is a poor substitute for thinking about coverage.
Regional databases are not interchangeable
“Regional database” describes a geographic orientation, not a single technical standard. Resources differ considerably in what they index and how they operate.
Feature to examine
Why it matters
Question to ask
Geographic coverage
The database may cover one country, several countries, or a broader region.
Does it actually cover the places relevant to my question?
Subject coverage
A regional database may concentrate on health, agriculture, education, or another domain.
Does its disciplinary scope fit my topic?
Source coverage
Some resources index journals absent from your international databases.
Which relevant journals or publication types does it add?
Language coverage
Regional literature may include locally important languages.
What languages are indexed and searchable?
Search functionality
Field searching, controlled vocabulary, truncation, phrase searching, and Boolean syntax may differ.
Can I translate my search strategy appropriately?
Time coverage
Historical coverage may begin or end at different dates.
Does its coverage match my review period?
Regional and multilingual searching often overlap
Geographic and linguistic coverage are difficult to separate. Locally relevant studies may be published in English, another international language, a national language, or several languages.
A regional database may make some of this literature easier to discover, but its presence does not guarantee comprehensive language coverage. You may still need to investigate how to find non-English research when searching primarily in English and whether translated terminology would improve retrieval.
Do not copy and paste one database strategy into another
A carefully designed search in one platform may not function equivalently in another. Databases differ in field codes, controlled vocabularies, phrase handling, truncation, wildcards, proximity operators, indexing practices, and interface capabilities.
If you add a regional database, translate the conceptual search strategy into the syntax and functionality of that resource. A technically invalid or poorly adapted query can create the appearance that a database contains little relevant research when the real problem is the search.
Regional databases are only one route into local evidence
A local evidence base may extend beyond bibliographic databases altogether. Government agencies, universities, research institutes, professional societies, repositories, and other organizations may distribute relevant research directly.
For questions where these publication forms are important, searching a regional database should be viewed as one component of a broader discovery strategy. If the literature is concentrated in reports, theses, or government documents , another search route may be necessary.
Watch Out
Do not add regional databases simply to make your methods section look more comprehensive. Every source should have a defensible relationship to the research question, and the search should be adapted to what that source can actually retrieve.
04 · A Practical Example
When a regional database changes the search strategy
Hypothetical Example
Reviewing community health interventions in Latin America
A researcher wants to synthesize evidence on community-based interventions implemented specifically in Latin American health systems. The initial search includes MEDLINE and a multidisciplinary international database.
Question The setting is not incidental. The review explicitly seeks evidence from Latin American countries.
Coverage check The researcher determines that LILACS contains Latin American and Caribbean health-sciences literature and can therefore reach sources that may not be represented adequately in the existing search.
Decision LILACS is added because its coverage matches both the geography and subject matter of the review, not merely because it is a regional database.
Search adaptation The concepts from the main strategy are translated into the database's available fields, terminology, and search syntax rather than copied mechanically.
Interpretation Records retrieved uniquely from the regional source are screened under exactly the same eligibility criteria as records retrieved elsewhere.
If the additional search identifies journals that appear relevant but are absent from the researcher's other databases, the next problem becomes finding research published outside major database indexes .
06 · What This Means for You
Decide based on what evidence the regional source can reach
The strongest reason to search a regional database is not that your study mentions a country. It is that the database plausibly provides access to relevant evidence that your other sources may not capture adequately.
A simple decision framework
If the research question explicitly concerns a country or region
Investigate whether suitable national or regional bibliographic databases cover locally important literature.
If relevant journals or languages are poorly represented in your existing databases
Give greater weight to a regional source that demonstrably expands that coverage.
If geography is incidental and existing sources cover the relevant discipline well
Do not add a regional database automatically. Assess whether it is likely to contribute useful evidence first.
If the regional database has weak search functionality
Adapt the search realistically, document the limitations, and consider complementary methods such as citation searching or targeted journal searching.
For systematic or scoping reviews, record why each source was selected and report it transparently. For less formal literature searches, the same reasoning remains useful even if the documentation requirements are lighter.
07 · A Quick Checklist
Before adding a regional database to your search
Before searching regionally, check:
Whether geography is substantively important to the research question rather than merely where some studies happen to occur.
Which countries, journals, document types, and years the regional database actually covers.
Whether it indexes locally important sources absent from your existing databases.
Which languages are represented and whether your search terms can retrieve them adequately.
Whether its subject coverage matches your research topic.
How its search syntax and indexing differ from the databases you have already searched.
Whether relevant local evidence also requires searching repositories, government sources, journals, or other resources outside the database.
09 · The Bottom Line
Search regionally when local evidence could materially improve the answer
The Bottom Line
Search a regional or national database when your question makes locally produced evidence important and your existing databases may not adequately represent the relevant journals, languages, countries, or publication systems.
Regional databases are usually deliberate complements rather than automatic additions. Examine what each resource actually covers, adapt your search to its functionality, and judge its usefulness by the relevant evidence it can reach.
11 · Cite this Guide
How to Cite This Guide
This guide is intended to be read, shared, and used in research, teaching, and academic work. If you draw on its ideas, explanations, or other content, please acknowledge the source by citing the guide. Doing so gives appropriate credit and helps your readers locate the original resource.
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