Learn how our advanced search query builder works and which search strategies you can use in Overton Index.
Our advanced search query builder guides you to create effective, precise searches. It helps you build complex queries, apply search strategies as they function in Overton Index, and refine your search with the query visualiser.
Using the query builder
This step-by-step guide introduces the query builder and shows you how to construct a simple search query for policy documents.
Directory of advanced search strategies
Boolean operators
- Operators like AND, OR and NOT combine search terms and control how terms relate within a query.
- Select operators from the dropdown that appears after a search term is entered.
Example: "covid-19" AND protection AND NOT masks
This query finds documents that contain “covid-19” and “protection” but do not contain the word “masks.”
Parentheses
- Use parentheses to group terms and control logical order.
- Search terms inside of the brackets are evaluated first as a separate expression.
- Add parentheses by clicking on the ‘Add group’ or ‘Add nested group’ option below the query line.
Example: (governance AND ("data science" OR "artificial intelligence")) OR "AI ethics“
This query finds documents containing governance and (data science or artificial intelligence), or contain the exact phrase AI ethics.
Phrase searching
- Search terms that are not contained within quotation marks will be searched for as individual words
income tax– will match documents where there are instances of income and tax but not necessarily adjacent
- Find documents where your words appear together in a phrase by selecting ‘exact phrase’
Example: "income tax" — this will match documents where income tax appears exactly.
Wildcard searches
Users can search for alternate ends of words using the ‘*’ wildcard. Wildcards are used in keyword searching to represent one or more characters. For example, a search for
Canad*
will retrieve documents that contain the words Canada, Canadian or Canadians.
One thing to note is that the ‘*’ wildcard can only be applied to single words and will not work for phrase searching using quotes.
Special characters and accents
Overton is sensitive to diacritics. For example, querying Overton for “nino” will return different results than a search for “niño”.
If the name of a researcher you’d like to search for on the people tab contains accented characters, we recommend including its special characters :
eg: “Bernhard Schölkopf ” rather than “Bernhard Scholkopf“
Proximity searches
To search for words occurring near each other you can use the ~N operator, where N is how many words are allowed in between each part of your phrase.
For example:
"data science"~1
will find documents containing the words “data” and “science” next to each other or with one word between them where “data” appears first and “science” appears second (e.g. “data science” and “data and science” would match, but “data indicates that science” and “science of data” wouldn’t).
Specific field searches
You can find policy documents with words within specific fields or in some cases, documents that have been assigned an specific identifier. A few things to note about searching within specific fields
- specific field searches must be at the start of your search query
- you can only search one specific field at a time
- all the words after the prepend will be included in your query
- you can combine specific field searches with other techniques like phrase searching, proximity searches and using Boolean operators.
The following prepends can be used to search within specific fields.
title:gender equality STEM
will return results with all the words anywhere within the title of a policy document
title:"tobacco packaging"
will return results with the exact phrase “tobacco packaging” within the title of a policy document
abstract:climate
will return documents that have the word “climate” in either their title or abstract. It is important to note that not all policy documents have available abstracts.
author:"Erica Smith" OR "E Smith"
will return articles authored by Erica Smith or E Smith (this prepend only works in the Search Scholarly Articles search).
domain:brookings.edu
will return documents that cite specific domains
If Overton collects a site-specific identifier like a catalog number or DOI (we only do this for certain sources), you can search using the id: prepend.
id:JRC127215 OR JRC127882
will return documents with a site specific ID matching JRC127882 or JRC127215 (in this example the identifiers are from the Joint Research Centre, an EU agency).
Semantic search
Overton supports semantic searching. Semantic searching focuses on meaning rather than exact keyword matching. Using 2 or more sentences following the similar: prepend will find policy documents that have a similar concept or theme.
similar: The document discusses the mental health impacts of climate change and provides guidance on how to maintain mental well-being during this challenging time. It highlights the various stressors associated with climate change, including extreme weather events, heatwaves, and droughts, which can lead to anxiety, depression, and post-traumatic stress disorder.
Learn more about ‘Searching for Similar Policy Documents.’