Creating Effective Searches

Identifying Search Terms

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To begin locating material that addresses our information need, we need to identify the viable search terms embedded in our research topics or questions. These are the key concepts that drive our information need and usually make good search terms.

Identifying key concepts involves analyzing an information need, identifying the main ideas related to it, and translating those concepts into search terms.

Searching for sources using all (or most) of the words in our research questions does not usually work well in library databases, the library catalog, or on the web. We often get too few useful materials.

The more thought we put into identifying our search terms, the more relevant our search results will be. Then, the time we invest in researching will be more productive.

Strategies for identifying search terms include

Once we've identifying viable search terms, we will need some strategies for creating effective searches in the online search tools. The next few pages offer tips for creating searches using phrases, Boolean operators (connectors), truncation, and wildcards, as well as tips for setting limits (specific boundaries) for searches.

Using Phrase Searches

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Most search tools do not automatically "tie" adjacent search terms together. The words are searched separately and then combined, so we frequently get results that are not on our topics.

Using phrases helps us create search terms with the words in an exact order. Phrase searches can enhance search accuracy and retrieve more relevant results. However, if we use uncommon phrases or phrases that are not recognized by the search tools, we'll get too few results.

The best strategy is to create phrase searches for terms that can be expected to appear in others' writings. For example, "high-stakes tests" is a commonly used term in the education field. Therefore, it would probably be a good phrase search.

Phrases are usually created by enclosing the search terms in quotation marks (e.g., "human resource management"). Some search tools, however, use other punctuation symbols for phrases. For example, we would use single quotation marks (apostrophes) to create phrase searches in the library catalog. Also, some search tools do not support phrase searches.

Reading the search help files in online search tools will tell us which symbols to use for phrases and other search strategies.

Trying different phrases, looking for clues in the articles we read, and keeping a research log helps us create effective searches. We can gain further control over searches by using Boolean operators (connectors), which are explained next.

Using Boolean Operators

Boolean operators were named after George Boole, a mathematician and the originator of algebra of logic (Boolean algebra) that became the basis for digital computer circuit design.

We use Boolean operators, also called connectors, in online search tools to connect our search terms so we can broaden (expand) and narrow (restrict) searches to increase the number of relevant search results we retrieve. The three most commonly used Boolean operators are AND, OR, and NOT.

Using Boolean operators between search terms lets us

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The Boolean operator AND is used to narrow (limit or restrict) searches. It limits the search results to items containing all the search terms connected with AND. Multiple terms can be combined with the AND operator to further restrict search results.

The image to the left illustrates the results of a search for "small group" AND decision-making. The purple shaded area represents the search results that would be retrieved -- only items with both search terms.

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The Boolean operator OR is used to broaden (expand) searches. It expands our search results to include items containing any of our search terms. Using the OR operator helps when we want to look for synonyms and alternative terms.

The image to the left illustrates the results of a search for "small group" OR decision-making. The purple shaded area represents the search results that would be retrieved -- any item containing one of the search terms.

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The Boolean operator NOT is used to narrow (limit or restrict) searches. It limits our search results by not retrieving items with the terms marked with NOT. The NOT operator should be used cautiously because it's easy to inadvertently exclude relevant material.

The image to the left illustrates the results of a search for "small group" NOT decision-making. The purple shaded area represents the search results that would be retrieved -- items with "small group" and no items containing the term decision-making.

NOTE: Some search tools require that Boolean operators be typed in all capital letters. Therefore, it is a good strategy to always capitalize them.

Boolean operators can be combined in many ways and used separately or together. Many search tools offer advanced search interfaces that let us choose Boolean operators from drop-down lists, as well as type them in search fields. These features give us quite a bit of control over our searches.

Watch a video about using Boolean operators created by The University of Auckland Library, NZ. This video explains what Boolean operators are and demonstrates using them in several different search interfaces.

Using Truncation

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Truncation allows simultaneous searches for variant forms of search terms. This technique is also called stemming because a word's "stem or root" forms the basis of search terms.

A truncation symbol is added to the end of a word's stem (e.g., manag*), which lets us search for other forms of the word (e.g., managers, management, managing) without having to type them all and connect them with the OR Boolean operator.

Truncation broadens searches,increases search results, and locates items that might be missed. For example, if we searched for "high-stakes tests," we might miss articles that only used the term "high-stakes testing." Truncating the search term to "high-stake test*" would locate items containing both terms.

NOTE: The truncation symbol in most online search tools is the asterisk (*). Some search tools, however, use other punctuation symbols for truncation. For example, we would use the dollar sign ($) to create truncation searches in the library catalog. Also, some search tools do not support truncation.

Reading the search help files in online search tools will tell us which symbols to use for truncation and other search strategies. Watch a brief truncation search demonstration created by Honnold/Mudd Library.

Using Wildcards

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Wildcard searches are similar to truncation searches. However, in wildcard searches the symbol is inserted within a word and used as a substitute for a letter (or letters) within a word.

This search technique helps us find items containing words that have some letters in common, but not all the letters (e.g., color and colour, advertise and advertize). Wildcard searches also help us locate items when we are not sure how to spell a word (e.g., Carlson and Carlsen). In addition, they help us locate items when different forms of words are created by internal changes (e.g., woman and women, man and men).

Wildcards broaden our searches, increase the number of items retrieved, and help us locate items we might miss due to how words are spelled.

NOTE: The symbol used to create wildcard searches varies quite. Also, some search tools have wildcard search symbols that will substitute for multiple letters. Therefore, reading the search help files in the tool you're using would be a good strategy before investing too much time in searching with wildcards.

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