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Racer Library Tutorial - MPA Program (POL 670, 671, 681, etc.)

Introduction to Search Techniques

TLDR - Boolean Operators

TL;DR - Boolean Operators

If you do not read the following section in entirety, here are some key takeaways.

  • Boolean operators: words to add in your search to narrow or broaden your search results
  • AND: find sources that include both terms -> Narrows/Limits your search (fewer search results)
  • OR: searches for sources with either term -> Expands/Broadens your search (more search results)
  • NOT: excludes sources that have a specific term -> Removes certain sources from your search (fewer search results)

Search Techniques

The first step in finding resources for your assignments is understanding some basic search techniques.

Keywords

When performing a simple search in a search engine like Google, it is easy to type in a phrase or sentence to explain what you need. When you type a phrase such as "how does a car work?" the search engine will use algorithms to determine what it thinks you meant, sometimes with mixed results. To locate the most relevant results quickly,  particularly when you start working in specialized databases, it is important to break down your research question into its key concepts, which can then be used as keywords in a database search. 

Example: How does caffeine affect the memory of college students?

To find the keywords in the sentence, you will first eliminate all the words that do not provide any meaning, so the remaining words will be considered your keywords to use in a search for information. In this sentence, words like “how” and “does” will be eliminated to leave the remaining words "caffeine," "memory," and "college students" to become our keywords for finding meaningful search results.

Boolean Search Techniques

One way to limit a database search is to use Boolean operators, words you can add to a search to narrow or broaden your search results. They are AND, OR, and NOT. You can usually find these words in a database's advanced search query area. And will narrow your search.

AND –If the main idea contains two or more ideas, you’ll want to use AND to combine those terms in your search statement. This automatically happens in search engines such as Google and Bing unless you tell them to do something different by using OR or- NOT.

For example, if you are interested in freshwater fishing, you would enter the terms “fish AND freshwater.” Your results would then include records that only contained both of these words. 

The overlapping green area in the diagram above represents the results from the “fish AND freshwater” search.

OR – If the main idea has several synonyms, use OR to combine them. Most search tools search for all terms using AND by default, so you need to use the term OR between terms to let it know you want to find any of the terms, not results with all the terms.

For example, if you are interested in finding information on mammals found in the Atlantic Ocean, you could enter the terms “whales OR dolphins.” The circles represent the OR search. All of the records that contain one or another or both of your search terms will be in your results list.

 

NOT – If the main idea has a common use that you want to exclude, use NOT to exclude that word. For example, if you were looking for information on all Atlantic Ocean fish except Bluefish, you would enter “fish NOT bluefish.” 

The larger green circle represents the results that you would retrieve with this search.


Advanced Search Techniques 

Special characters can be used in keyword searches to create a more specialized search. The main special characters that are used are quotation marks, the question mark, the asterisk, and parentheses.

Use Quotation Marks for Phrases

Put quotation marks around any phrases among your terms so that the phrase is what’s searched for, rather than the separate words. A good example is using quotation marks around “Common cold” instead of just typing common cold without quotation marks. Without those quotation marks, think how many sources Google or other search tools would find to waste your time on things that have nothing to do with the sniffles.

Use Wildcard and Truncation Symbols to Broaden

Consider using the wild card or the truncating symbol to find variations of a word. For instance, the wildcard symbol in wom?n finds both woman and women, and the truncating symbol in mathematic* finds mathematics, mathematically, mathematician, etc.

Use Parentheses with Multiple Operators

When a search requires multiple Boolean operators (AND, OR, NOT, or their symbols), you must use parentheses to group the appropriate terms with each Boolean operator. The resulting statements connect terms, remove terms, and organize search terms in ways that result in complex and precise searching.

Never use parentheses unless you are using multiple Boolean operators.