Boolean Searches in Scopus: Understanding Operator Precedence & Best Practices

When searching in Scopus, users have access to a comprehensive, curated and trusted academic database. It can be used to find relevant authoritative research, identify top experts and gain strategic insights.  Combing through content from over 7000 global publishers to find relevant research for your project can seem daunting, but Scopus provides tools to quickly refine your search.   Among these tools is Scopus Advanced search which allows you to fine-tune the scope of your search using field codes, proximity operators and/or Boolean operators 

When conducting literature searches in Scopus, the structure of a Boolean query can significantly impact both the number and relevance of the results retrieved. Since Scopus' search logic was designed with librarians in mind, many beginner and intermediate users may not be fully aware of Boolean Operator Precedence and best practices for using parentheses. These factors are crucial in determining how search terms are processed and in what order. 

In this article, we’ll explain how Boolean logic is applied in Scopus and share best practices for constructing queries. Additionally, we’ll introduce an upcoming update to Boolean operator precedence, set to roll out in fall 2025, with full implementation expected in early 2026. 

Understanding Boolean Operator Precedence in Scopus 

Boolean operators define how search terms interact. However, the order in which these operators are applied can significantly impact the results, especially if parentheses are not used to properly group key concepts. Basic or Advanced lexical searches with multiple operators, Scopus processes queries in the following order of precedence: 

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Best Practices for Constructing Boolean Queries w/ proximity in Scopus 

Proximity searching is used to narrow searches by finding words that are next to, or near, or within a specified distance from each other. This is useful when you are looking for concepts that might be expressed by multiple different phrases. 

Example 1: Searching for Tidal Energy Research 

Consider these three queries, all with the same user intent. However, one of them produced unexpected results: 

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Example 2: Enhancing Complex Queries 

Many users assume complex searches require lengthy queries, but grouping enhances clarity and efficiency. Using parentheses to structure searches ensures logical relationships between keywords, improving precision and yielding better results. 

Consider these two queries: 

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Example 3: Comparison of Different Scopus Search Types 

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Upcoming Changes to Boolean Operator Precedence (Fall 2025/Early 2026)  

Starting in late 2025, Scopus will gradually update Boolean operator precedence to align with the current industry standards and finalize the update in early 2026.  

If your queries do not have parentheses to specify precedence, Scopus will follow this new default order when the new update is rolled out:  

1. AND NOT  
2. AND = the (implicit) default  
3. OR (lowest precedence) 

Users who prefer the old precedence rules can still enforce them by manually grouping terms with the correct parentheses.

Final Thoughts 

Understanding Boolean operator precedence and search types in Scopus is crucial for retrieving the desired accurate and comprehensive search results.  The best way to gain an understanding of Boolean concepts is to experiment.  Use Scopus Advance Search search with the concepts shown here with your next reserch project. Just remember to apply these best practices, to maximize the effectiveness of Boolean searches in Scopus:  

• Use parentheses ( ) to control precedence and avoid unexpected results. 
• Keep queries concise and structured to improve readability and efficiency. 
• Be aware of the different search types and what they are suitable for based on your need.  
• Prepare for the upcoming Boolean operator precedence update by familiarizing yourself with the new precedence rules AND making sure to group your queries if you want to specify a certain precedence.