LibGuides: DTS 468: Advanced Search Strategies

What are Boolean operators?

They are a search technique that helps your search string be as relevant and precise as possible.

The three Boolean operators are AND, OR, and NOT.
They typically appear on Advanced Search pages, usually in a drop-down menu.
- The default for the drop-down menu is always AND.

How to use them:

Basic search: social media
- With a simple search for "social media," let's say you get 180K results
Advanced Boolean search #1: social media AND teens
- The Boolean AND will narrow your search.
- Adding "AND teens" narrows those 180K results down to only the sources that mention both key concepts, perhaps to 130K
Advanced Boolean search #2: social media AND teens OR youth
- The Boolean OR will broaden your search.
  - Tip: OR means MORE.
- Use OR when including synonyms and related terms. This means you're essentially doing two searches at once. Perhaps now the result number increases to 135K.
Advanced Boolean search #4: social media AND teens OR youth NOT Twitter
- The Boolean NOT will narrow your search by excluding terms from your results. Perhaps now your result number is 120K.

Single search box versus Advanced search boxes

From a Single (i.e. simple) Search box:

Type your Boolean operator in all caps in the search box between your search terms.
- Some database search engines can't 'see' those operators unless they are capitalized.
- Some databases automatically 'assume' a Boolean AND to be in between two or more search words, but not all do, so it's safest to type the Boolean connectors in capital letters.

Screenshot of key concepts in one search box using Boolean operators in all caps

From Advanced Search boxes:

Many databases offer several search boxes (and the ability to add more if needed) to accommodate all your search terms.
In these cases, to add a Boolean operator to your search, you simply choose the one you want from the drop-down menu that is available in between each pair of search boxes.

Screenshot of key concepts in four separate search boxes using the Boolean operator drop-down options

What are Subject Headings and Keywords?

Subject headings describe the content of each item in a database. Use these headings to find relevant items on the same topic. Searching by subject headings (a.k.a. descriptors) is the most precise way to search article databases.
- Note that many databases list subject headings alphabetically. For example, if you look for "Movie Theatres" under "M" you will find nothing, as they are listed under the letter "T" for subject heading "Theatres - Movies."
Keyword searching is how you typically search web search engines. Think of important words or phrases and type them in to get results.

Here are some key points about each type of search:

Keywords	Subject Terms
Natural language (conversational) describing your topic A good place to start your search	Pre-defined "Controlled Vocabulary" or higher order terminology Used to describe the content of each item (book, journal article) in a database
More flexible to search with Can combine together in many ways	Less flexible to search with Need to know the exact controlled vocabulary term
Database looks for keywords anywhere in the record - not necessarily connected together	Database looks for subjects only in the subject heading or descriptor field, where the most relevant words appear
Broadens your search, providing more results. But may yield too many or too few results, depending on the topic and the keywords	Narrows your search providing fewer results. If search yields too many results, use a sub-heading to focus on one aspect of the broader subject
May yield many irrelevant results, for example: Dogs Skin Cancer High Blood Pressure Sleeplessness	Usually yields results that are very relevant, for example: Canines Skin Neoplasms Hypertension Insomnia
Image: Screenshot of keywords in a simple search, with Boolean operators underlined in orange.	Image: Screenshot of subject terms from a sample search in Summon.

Question mark in talk bubble If you have any questions when doing research, simply Ask a Librarian!

What is Phrase Searching?

Phrase searching is the most precise search technique of all, because most research topics are made up of complex key concepts, rather than just a single term.

How to perform a phrase search:

When you enclose multiple words with double quote marks (") on either side, you are telling the search engine that you want only results with those words right next to each other, in that exact order, rather than separating them.
This is a good technique to use when you are searching for a 'term of art' (i.e., a term, in this case, one containing multiple words, that has a specialized meaning in a particular field or profession). In other words, everyone when communicating about that topic uses that exact phrase.
Some databases assume that words typed next to each other should be searched as phrases, while others automatically put the Boolean operator AND between your search terms, requiring that all the words be present, but not necessarily adjacent to each other. These searches can retrieve very different results, so be aware of how the databases are treating your search phrases.
Another example of when using a phrase search would be useful is when you are seeking something like a book or movie title, or someone's name.

Examples:

"genetic engineering"
"return on investment"
"peer tutoring"
"social media"
"myocardial infarction"
"Shakespeare in Love"
"Of Mice and Men"
"President Lincoln"
"Steve Jobs"

Question mark in talk bubble If you have any questions when doing research, simply Ask a Librarian!

What is Proximity Searching?

Similar to phrase searching, Proximity Searching specifies to the database that the words you are searching are within a certain proximity of each other. To do this, you usually type a proximity operator (will vary by database) as well as a number, between two search terms. Proximity operators are more specific than Boolean operators and make your search more precise.

Proximity operators also vary by database, but some common ones include:

Near operator (N#)

Near finds the words if they are a maximum of x number of words apart from one another, regardless of the order in which they appear.
- Example: oil N4 disaster OR clean-up OR contamination
  - will retrieve: contamination of oil, as well as contamination of the lubricating oil
- Example: cloning N3 human
  - will retrieve cloning of humans, human cloning, etc.

Within operator (W#)

Within finds the words if they are within x number of words of one another, in the order in which you entered them.
- Example: tax W3 reform
  - will retrieve: tax transition reform
    - Why? reform is within two words of tax, and is in the order in which the search terms were entered.
  - will not retrieve: reform of income tax
    - Why not? Even though reform is within three words of tax, it is not in the order in which the search terms were entered.
- If no number is given, then it specifies an exact phrase.
  - genetic w engineering searches the phrase genetic engineering and is similar to using quotation marks

Each database will have a Tutorial or Help section in their main menu, so take some time to visit those to find out how to search by phrases or to specify proximity, since they may have unique rules.

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What is Truncation?

Truncation, also called stemming, is a great way to expand your search, as it broadens your results to include various word endings.

It is especially useful when you are researching a topic that makes use of words where there can be both singular and plural endings, or word variations where there can be multiple forms.

To use truncation, enter the root of a word and put the truncation symbol at the end.

What is the truncation symbol?

It varies by database, though many tend to use an asterisk (*).
- Check the database' tutorial or help screens to find out which symbols are used.
- Common symbols include: *, !, ?, or #

This prompts the databases' search engine to seek out for any variant form that can be made from that root word. Take care exactly what root you use as your search term, in case there might be wildly unrelated words that can be made from it which have nothing to do with your topic.

Examples:

child* will bring back results including: child, children, children's, childhood
plan* will bring back results including: plan, plans, planning, planner, planners
genetic* = genetic, genetics, genetically

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What are Wildcards?

Wildcards are a great way to expand your search, as it broadens your results to include word variants and multiple spellings.

It is especially useful when you are researching a topic that makes use of words where there are alternate spellings, such as variations between American and British spellings.

To use a wildcard, replace a letter in your search term with the database's wildcard symbol.

What is the wildcard symbol?

It varies by database, though many tend to use a question mark (?) or exclamation mark (!)
- Check the database' tutorial or help screens to find out which symbols are used.

Examples:

colo?r will bring back results containing either the word color or colour as results.
wom!n will bring back results containing either the word woman or women

Question mark in talk bubble If you have any questions when doing research, simply Ask a Librarian!