Should You Pilot a Search Strategy Before Committing to It?

Should You Test a Literature Search Before Treating It as Final?

A database accepts your search string. It returns results. The first few records look relevant. Technically, the search works.

That does not mean the search strategy is ready.

A functioning query can still contain missing synonyms, unnecessarily restrictive concepts, incorrect Boolean logic, poorly chosen subject headings, ineffective truncation, or terms that retrieve enormous amounts of irrelevant material. More importantly, it can fail to retrieve studies you already know should be there.

Testing the strategy before committing to it gives you an opportunity to discover these problems while they are still relatively inexpensive to fix.

Yes, Treat the First Search as a Draft

A Search Strategy Is Something You Develop, Not Something You Type Once

Why the first search is rarely the final search

You usually begin search development with an imperfect understanding of how the literature describes your concepts. The terminology in your research question may differ from terminology used by authors, indexing systems, older publications, neighboring disciplines, or particular databases.

Running an initial search allows the literature itself to expose some of that vocabulary. Relevant records may reveal synonyms, subject headings, acronyms, variant spellings, product names, methodological terminology, or older expressions that were absent from your initial plan.

Cochrane's guidance on searching describes search-strategy development as an iterative process. It recommends combining controlled vocabulary with free-text terms and examining relevant records for additional terminology rather than assuming that the initial set of words will be sufficient.

This is why doing a literature search systematically involves more than constructing one Boolean expression and pressing Search.

What exactly are you testing?

A useful pilot examines several different properties of the strategy.

No single diagnostic tells you that a search is “correct.” Piloting is better understood as stress-testing different parts of the strategy.

Inspect relevant records for terminology you missed

One of the simplest forms of piloting is to run the draft search, identify several clearly relevant records, and inspect their titles, abstracts, author keywords, and database subject headings.

Ask how those records describe each concept. If a recurring synonym is absent from your strategy, determine whether adding it retrieves relevant material not already captured by existing terms.

For example, a search concerning generative AI may initially use terms such as generative artificial intelligence and large language model. Relevant records might reveal widespread use of specific system names or phrases such as AI-assisted writing. Those expressions may warrant testing.

The objective is not to add every term you encounter. Search strings can become impressive archaeological sites if nobody occasionally removes the rubble. Add terminology because it improves retrieval of the concept, not because it happens to appear in one paper.

Check whether individual terms are creating noise

Piloting should also examine irrelevant records.

If a term retrieves large numbers of unrelated studies, determine why. Perhaps an acronym has several meanings. A truncated root may be too broad. A phrase may be used differently in another discipline. A keyword may need proximity searching or field restriction.

Do not automatically delete noisy terms, however. A term can retrieve substantial noise while also identifying relevant studies that no other term finds.

The relevant question is therefore not “Does this term retrieve irrelevant records?” Almost every useful broad term does. Ask whether its unique contribution to relevant retrieval justifies the additional screening burden.

Test the effect of adding restrictive concepts

Searches often become narrower during development. You may add a population block, an outcome, a methodological concept, a date restriction, or another condition because the original search retrieves too much.

Test the consequences rather than assuming the change is beneficial.

Compare retrieval before and after the restriction. Check whether known relevant studies disappear. Inspect records that are removed. If the restriction improves precision while preserving relevant retrieval, it may be useful. If it removes studies that satisfy your eligibility criteria, the apparent improvement may be misleading.

This is particularly important because overly strict search criteria can hide important evidence.

Do not judge the pilot only by the number of results

A search returning 5,000 records is not necessarily worse than one returning 500. Likewise, a search returning 50 records is not necessarily elegantly precise.

Result count is diagnostic information, not a quality score.

If retrieval is unexpectedly large, examine why. An ambiguous term may be responsible. The research question itself may be broad. The strategy may intentionally prioritize sensitivity. Conversely, unexpectedly few results may reflect a genuinely small literature or an unnecessarily restrictive strategy.

Before narrowing a large result set, distinguish whether the search or the underlying conceptual scope has become too broad.

Known relevant papers are useful test cases

If you already know several studies that satisfy the conceptual scope of the review, check whether the draft strategy retrieves them.

This provides a concrete test of search behavior. A missing paper can reveal terminology that was overlooked, indexing differences, a concept that is too restrictive, or an inappropriate database field.

Failure to retrieve one known paper does not automatically prove that the entire strategy is poor. The paper itself may be unusual, incorrectly indexed, outside the database's coverage, or impossible to retrieve through the concepts you reasonably chose. The failure needs diagnosis.

The diagnostic process deserves particular attention because testing whether the strategy can find a paper you already know should be there is one of the most interpretable checks available during search development.

Peer review can test things your own pilot misses

Search developers become familiar with their own logic. That familiarity can make errors harder to see.

For systematic reviews, external review by an information specialist or another suitably experienced searcher can therefore add another layer of quality assurance. The PRESS guideline provides a structured framework for peer review of electronic search strategies, including the translation of the research question, Boolean and proximity operators, subject headings, text words, spelling and syntax, and limits and filters.

Piloting and peer review are complementary. Piloting asks how the strategy behaves. Peer review asks whether another knowledgeable person can identify conceptual or technical problems in how it was constructed.

Keep a record of meaningful changes

If piloting leads to changes, record them. You do not necessarily need to preserve every experimental keystroke, but consequential decisions should remain traceable.

For a formal review, this may include the draft strategy, terms added or removed, changes to limits or filters, the rationale for major revisions, the date the final search was executed, and the exact final strategy for each database.

That documentation also supports reproducing the literature search later.

How Piloting Can Reveal a Search Problem Before Screening Begins

The pilot did not prove that every relevant paper would be found. It did something more realistic: it exposed weaknesses that were invisible when the researcher merely looked at the first page of results.

Common Mistakes When Testing a Search Strategy

Build, Run, Inspect, Revise, Then Commit

Treat search development as an iterative methodological task. Construct a defensible first version, run it, inspect relevant and irrelevant retrieval, test known studies, and revise only when the evidence from that testing gives you a reason.

Once the strategy behaves reasonably, preserve the version you intend to use and document subsequent substantive changes. That creates a clear boundary between search development and the final search used to identify evidence.

Before You Finalize the Search Strategy

Questions About Piloting Literature Searches

Do Not Let the First Working Search Become the Final Search by Accident

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