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2.a. The Language of Search Engines
 It is a capital mistake to theorize before you have all the evidence. It biases the judgment. Sherlock Holmes
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Search engines are your helpers. They are information assistants who help you find the answers to your problems. Like any other assistant, the degree to which they are able to help depends on the degree to which you are able to tell them what you want. Therefore, communicating with your search engine is a critical part of the search process.
Search engines need to know what information you seek, and they need this desire described in a logical way, since they are computers after all. The language that we traditionally use to talk with computer-based searching tools is called Boolean, named after George Boole, an English mathematician of the 19th century.
In Boolean Logic we use keywords to describe what words to consider when searching for information that is relevant to our information quest. We also use operators to describe the relationships between our keywords and the information that we seek. The basic operators are AND, OR, and NOT.
Let's use an example to explore how we would use Boolean Logic to search for information on the Internet. We will look for information about Native Americans in the state of Ohio.
| Concept | Explanation | Example |
| Keyword | A keyword is a word or term that we want the search engine to consider in looking for relevant information. In our example one word that would likely appear in a web page about Native Americans is Indian. | Indian |
| OR | In many cases, there may be a synonym of our keyword that might appear in the web page instead of the keyword we have already chosen. So we will want to expand the number of pages that the search engine sends us to include the ones using the synonym. In the case of our example, many web pages would likely use the term Native American, which is more commonly used today than Indian. In this case we would use the operator, OR, to say that we want web pages with either the word Indian or the term Native American. | Indian OR Native American |
| AND | Since we are looking for information about Native Americans in the state of Ohio, then an additional keyword will be Ohio. We want to narrow the web pages that we get to only those about Native Americans in Ohio, so we will say that both terms must be present. Here is where we will use AND. | Indian OR Native American AND Ohio |
| NOT | As we think through the information that we are likely to receive, we realize that there is a baseball team in Cleveland, Ohio called the Indians. We will want to filter out all web pages about the baseball team. So we will add a new keyword, baseball, and connect it to our search express with the operator, Not. We are saying that the acceptable web page should NOT have the keyword baseball in it. | Indian OR Native American AND Ohio NOT baseball |
| quotes " " | Just as we use commas, question marks, and other punctuation to help communicate with people, we use special symbols to clarify what we want from a search engine. One example is the use of quotation marks to define phrases. In our example, Native American is going to look like two separate words to the search engine that could each appear any place in the web page. To communicate that these two words belong together as a distinct phrase, we use quotes. | Indian OR "Native American" AND Ohio NOT baseball |
| Parentheses ( ) | Each operator
in a search expression defines a distinct keyword concept. Keyword 1 AND Keyword 2 Keyword 3 OR Keyword 4 Keyword 5 NOT Keyword 6 A keyword concept can consist of:
Individual keyword concepts are marked by enclosing them in parentheses. In our example, the following are distinct keyword concepts: Indian (Indian OR "Native American") ((Indian OR "Native American") AND Ohio) The final keyword concept, the one that includes all constituent keyword concepts is called our search expression. |
((Indian OR "Native American") AND Ohio) NOT baseball |
Admittedly, Boolean Logic is not the simplest thing to understand or teach. However, it is a very effective way to communicate with search engines, refining your request for specific information resources.
To make things easier for casual users, Internet search engines have developed alternatives to traditional Boolean Logic. One of the most common conventions is the use of pluses (+) and minuses (-), to indicate which terms must (+) and must not (-) be present in the returned documents. Each search engine has developed its own version of these searching conventions, each trying to improve upon these standards, and this evolution of the search language continues. None is perfect and you will find that finding information from the Internet is more a process than the click of a button.
Section : Finding Digital Resources
Page 1: Topic-Oriented Directories
Page 2: Search Engines
a: The Language of Search Engines
Page 3: Net-Smarts -- or becoming Netwise
Page 4: S.E.A.R.C.H.
