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Becoming a Database Whisperer: Using Search Modifiers

Terms and concepts to know for this lesson:

Boolean operators - search functions that are used to connect and define the relationship between your terms. Tools for improving the precision and comprehensiveness of your databases searches.

Precision - Is your search narrow enough that you don't have to sift through a bunch of stuff totally unrelated to your topic?

Comprehensiveness - Is you search broad enough that you are returning results on all of the useful information on your topic?

In the previous lessons So What Should I Write On? Researching and Developing a Topic and I Like It, But Will It Work? Developing a Feasible Topic, you learned how to develop a research topic that is both interesting and feasible. You also learned how tools like Google and Wikipedia can be a great place to start researching a topic, as they provide you with background information as well as some key ideas and terms that will be central to your topic.

You learned in What is a "Good" Source? Determining the Validity of Evidence that you may want to consider using scholarly journals as evidence to support your argument. The library offers access to thousands of scholarly journals, which you can access through databases in ResearchPort.

Databases like these are often very literal. When you type words into a search box in a library database, the database searches for those words and only those words, just as you put them in. If the resources in the database use different words to describe your topic, you may not find them. But what if you could speak the database's language and tell it exactly what you wanted in a way that it understood?

To actually find sources relevant to your topic within those databases, you may want to consider using Boolean operators and other search modifers. These are tools for improving the precision and comprehensiveness of your search within a database. This lesson will teach you how to "speak database," with the following five modifiers:

AND
OR
NOT
* (wildcard)
"xxxx xxxxx" (phrase searching)

Boolean Operators

The words AND, OR, and NOT are specially reserved by most databases as modifiers to help you link concepts together. These are called "Boolean operators."

AND: When you need to find two things together

Any time you need to find two concepts together, use the operator AND. This will find you a smaller set of results that contains both of your concepts at the same time.

river pollution AND lake pollution

(You want to find stuff that talks about pollution in both of these places.)

OR: When either option will do

Whenever you need to expand your search results to include multiple options, and either of those options will do, use OR. This will find you a larger set of results that contains either concept A or concept B or both.

river pollution OR lake pollution

(You just want stuff on pollution in some kind of fresh water. Either is fine.)

NOT: When you don't want to find something

Whenever you want to exclude concepts from your search, use NOT. This will give you a smaller set of results that only includes the concept you want and not the concept you've excluded. This will also exclude results that contain both concepts.

river pollution NOT lake pollution

(You only want stuff on pollution in rivers. Pollution in lakes is not desired.)

Wildcards and Phrasing

Two other helpful search modifiers are the wildcard character (*) and using quotes to keep words together as a phrase.

* [wildcard]: When different forms of the word are all valid

The symbol * stands in for other letters at the ends of words. This is helpful for telling the database you will accept other forms of a word in your search results.

pollut* AND cancer*

"xxxx xxxxx" [phrase searching]: When you want to keep phrases together

Sometimes just looking for words isn't specific enough, and you'll only be interested in words that are found together in a particular order. Search for those words together in quotes just as you would like them to appear.

"river pollution" AND cancer

Using Modifiers Together

You can use as many modifiers as you want at once. If you want to use multiple modifiers, try nesting your searching using parentheses. These operators work just like math, so parentheses come first in the order of operations.

For example, let's say I wanted to learn more about the gray wolf, and its status on the endangered species list. I could just do a search for:

gray wolf AND endangered

But there will be some problems with this search - it doesn't account for the alternate spelling of gray, or for the plural form of wolf. And because I did not place quotes around gray wolf to keep it together as a phrase, I might get results that are not just specifically about this kind of wolf, but rather any article that just happened to include the word gray and the word wolf. A more precise and comprehensive search would look like:

(“grey wol*” OR “gray wol*”) AND endangered

Conclusion

Use AND, NOT, "xxxx", to narrow your search results down if your initial searches are returning too many results unrelated to your topic - these modifiers make your search more precise. Use OR, *, if your initial searches are not returning enough results - these modifiers make your search more comprehensive.

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