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Systematic Reviews: Search Strings

A Synthesis and Evaluation of existing evidence

Search String

A search string is a combination of search terms, operators, and modifiers used to query a database or search engine to retrieve relevant information. In the context of literature searches, a search string is constructed to find academic articles, research papers, or other scholarly materials on a specific topic.

  1. Search Terms: These are the words or phrases that represent concepts or aspects of the research topic. They can include keywords, phrases, or controlled vocabulary terms (e.g., Medical Subject Headings - MeSH terms in PubMed). Search terms should be selected based on their relevance to the research question and may include synonyms, alternate spellings, or related terms.

  2. Operators: Operators are special characters or words used to connect or modify search terms to refine the search results. Common operators include:

    • AND: Retrieves records containing all search terms. It narrows down the search results by requiring all specified terms to be present.
    • OR: Retrieves records containing any of the search terms. It broadens the search results by including records that contain at least one of the specified terms.
    • NOT: Excludes records containing a specific term. It helps to refine search results by excluding irrelevant records.
  3. Modifiers: Modifiers are additional parameters or settings applied to the search string to customize the search. They can include:

    • Truncation: A symbol (usually an asterisk ) added to the root of a word to retrieve variations of the word. For example, searching "child" will retrieve results containing "child," "children," "childhood," etc.
    • Phrase Searching: Quotation marks (" ") used to indicate that search terms should appear together as a phrase in the search results. For example, searching "climate change" will retrieve results where the words "climate" and "change" appear adjacent to each other.
    • Boolean Parentheses: Parentheses () used to group terms and operators to specify the order of operations in complex search strings.

("climate change" OR global warming) AND (impact OR effect) NOT adaptation

In this example:

  • "climate change" OR global warming: Retrieves records containing either the phrase "climate change" or the term "global warming."
  • impact OR effect: Retrieves records containing either the term "impact" or the term "effect."
  • NOT adaptation: Excludes records containing the term "adaptation."

Combining these components allows researchers to construct search strings that effectively retrieve relevant literature on their topic of interest.