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A good search strategy will include:
Steps for creating an effective search:
When formulating a research question, it's important to identify the key concepts that the articles should address. Focus on important nouns and leave out words that don't contribute to the search, like adjectives, adverbs, prepositions, and verbs. If you're not familiar with the topic, consider consulting secondary sources, such as books or review articles, to pick up initial terminology and background information. You can use a search framework like PICO to guide your search strategy by deciding which concepts to group.
Select an appropriate database and search interface to begin your search. It is important to consider the scope and coverage of the database, as well as the presence of a controlled vocabulary/thesaurus. You can find database suggestions in the Library Research Guides.
Please ensure to identify appropriate search terms, including alternative terms, synonyms, and related terms for each search concept. Make sure the terms are neither too broad nor too narrow. Utilize the thesaurus of the selected database, such as the National Agricultural Library Thesaurus (NALT), CABI Thesaurus, or Medical Subject Headings (MeSH) for this task. Focus on the most essential and relevant terms. Additionally, consider variations in search terms, such as truncation, spelling differences, abbreviations, and opposites.
When developing search statements, use quotation marks around phrases to search for the exact phrase rather than separate words. You can use wildcard or truncating symbols to find variations of a word. For example, forest* finds forestry, forester, forestal, etc. To do more precise searching, combine search terms using Boolean operators such as AND and OR. This narrows your search and makes it more precise. When using more than one Boolean operator, use parentheses to group the terms. Databases and search engines differ on how they search, so it's best to either group concepts with parentheses or use separate search boxes to be most explicit. You can create single-line queries in a separate text document and then copy and paste your search query into the database, or you can run and combine multiple record sets directly in the database.
The objective of a comprehensive search strategy is to find all or most of the potentially relevant articles. This can be achieved by expanding the search query with additional terms to see if more relevant articles are found. You can also ensure the uniqueness of results by comparing different search query results (e.g., search query #1 NOT search query #2). It's important to check the search query for completeness by adding potential search terms. One effective practice is to review the top retrieved articles (sorted by relevance) for additional search terms and synonyms that can be included in the search query.
Please ensure to carefully assess your search results. Evaluate your search by checking for relevant articles that you have already identified, sorted by their relevance ranking. If you find that not all the relevant references you know of are retrieved, adjust the search query as needed. Keep in mind that you should balance your search strategy with the intended goal of the search. If the search is too specific or too broad for your goal, you should modify it accordingly.
The PICO (Population, Intervention, Comparison, Outcome) framework is a popular framework for developing focused questions for intervention studies and quantitative systematic reviews.
| Population | What are the characteristics of the patient or population? |
| Interventions (or Exposure) | What do you want to do with the population? |
| Control | What is the alternative to the intervention? |
| Outcome | What are the relevant outcomes? |
Example: How effective are on-farm conservation land management strategies for preserving ecosystem services in developing countries?
The SPIDER framework is an alternative search strategy tool (based on PICO) for qualitative/mixed methods research.
| Sample | Who is the sample or population of interest? |
| Phenomenon of Interest | What is the phenomena of interest? A defined event, activity, experience or process? |
| Design | What types of study methods are you interested in? |
| Evaluation | What are the evaluation outcomes? |
| Research type | What type of research are you interested in? Qualitative or mixed method (qualitative & quantitative)? |
Sample topic: What are the experiences of women undergoing IVF treatment?
S - Women
PI - IVF treatment
D - Questionnaire or survey or interview
E - Experiences or views or attitudes or feelings
R - Qualitative or mixed method
SPICE can be used for both qualitative and quantitative studies. SPICE stands for Setting (where?), Perspective (for whom?), Intervention (what?), Comparison (compared with what?) and Evaluation (with what result?).
Sample topic: What are the coping skills of parents of children with autism undergoing behavioral therapy in schools?
S - Schools
P - Parents of children with autism
I - Behavioural therapy
C - None
E - Coping skills
OR either (or both) term present
(example: forest OR woodland)
AND both (or all) terms present
(example: “climate change” AND agriculture)
NOT removes a term
(example: urban NOT rural)
Use OR to connect variations representing the same concept. In many search interfaces you will want to put your OR components inside parentheses like this: ("invasive species" OR "Invasive alien species" OR “non-native species” OR "introduced organism"). These are now lumped together into a single invasive species concept for your search.
Use AND to link different concepts. By typing ("invasive species" OR "Invasive alien species" OR “non-native species” OR "introduced organism") AND (freshwater OR lake OR pond Or river)—you are directing the database to display results containing both concepts.
NOT eliminates all results containing a specific word. Use NOT with caution. The term excluded might be used in a way you have not anticipated, and you will not know because you will not see the missing results.
More information about using Boolean operators: Research Basics: Using Boolean Operators to Build a Search
Use parentheses to group similar terms together if you are not sure what term might be used in a search.
More about Search Statements: https://ohiostate.pressbooks.pub/choosingsources/chapter/search-statements/
Thesaurus terms will help you capture variations in words and spellings that researchers might use to refer to the same concept, but you can and should also use other mechanisms utilized by databases to do the same. This is especially important for searches in databases where the thesaurus is not specialized for your topic.
Note: Proximity symbols vary from database to database. Some use Near plus a number, while others use N, ADJ or W. Always check the database help section to be sure that you are using the right symbols for that database.
More about Search Statements: https://ohiostate.pressbooks.pub/choosingsources/chapter/search-statements/
Truncating a word mean typing the start of a word, followed by a symbol, usually an asterisk (*). This symbol tells the database to return the letters you have typed followed either by no letters (if appropriate) or letters. It is an easy way to capture a concept that might be expressed with a variety of endings.
Sometimes you need to adjust where you truncate to avoid irrelevant results. See the difference between results for nutri* or nutrit*
nutri* will return nutria, nutritious, nutrition, nutritional, nutritionally, nutricereals, nutrikinetics, nutritionists, nutrative, nutrient, nutrients, nutrigenetics, nutrigenomic, nutrigenomics and more.
nutrit* will return nutritious, nutrition, nutritional, nutritionally, nutritionists, and nutritive.
Inserting wildcard symbols into words covers spelling variations. In some databases, typing organi?ation would return results with organisation or organization, and flavo#r would bring back results with flavor or flavour.
Note: While the truncation symbol is often *, it can also be $ or !. Wildcard symbols also vary from database to database. $ or ? are sometimes used. Always check the database help section to be sure that you are using the right symbols for that database.
In building a search you can combine all the tools available to you.
More about Search Statements: https://ohiostate.pressbooks.pub/choosingsources/chapter/search-statements/
When searching the literature, consider the following sources for a comprehensive search:
