Boolean Search Concepts

 Boolean Search Concepts

Boolean searching was developed by George Boole, an English mathematician. Essentially, Boolean searches provide the ability to combine words and phrases using the operators AND, OR, NOT to refine your search.

  • Using AND narrows a search to include results where all the words you are looking for are present.
  • Using OR broadens a search to include results that contain either of the words you’re looking for.
  • Using NOT narrows a search by excluding the words after the NOT operator.

For example, let’s say you have a person that you are looking for that has a common name such as “John Smith.” You know that a simple search nation-wide or state-wide would provide too many results for you to ponder. But what if he lived in a smaller town, such as Saugatuck, Michigan. A good search criteria would be “John Smith” AND Saugatuck. This would narrow the search results to articles that contain the phrase “John Smith” and those articles that contain the word “Saugatuck”.  See how this would help you?

The use of the operators “OR” and “NOT” operate similarly, except OR would provide pages which contain any of the words that you specify, and “NOT” would eliminate those results that have that word.  You can also combine multiple operators in one search.

Depending on the online collection’s software, you can sometimes actually write the AND, OR or NOT in the search box. The Community History Archive software includes this feature.

The Community History Archive software provides a variety of ways to utilize the AND, OR, and NOT operators.

The Basic Search

In the box where it says” SEARCH”, you can enter a search string as in the above example: “John Smith” AND Saugatuck.  If you choose a search string with the OR or NOT operators, it will also be entered in the “search” box.

The Keyword Search

The same exact rules apply when using the “Search by Keywords” function. You would enter the search string that contains the AND, OR, and NOT operators in the top “Search” box.

The Advanced Search

Use of the Advanced Search function provides you with even more options:

In the middle after it says, “Find Pages With”, there are 4 boxes.  The first (“This exact word or phrase:”) is for what I call “phrase searching”.  Phrase searching is similar but DIFFERENT than the Boolean AND.  Our research example above of “John Smith” in double quotes, is an example of searching for a phrase.  It operates similarly to John AND Smith, yet is different.  HOWEVER – a phrase search implies that the words John and Smith are right next to each other in the text, while using a search criteria of John AND Smith, the words do not necessarily have to be next to each other on the page. There is a difference.

The second box, “All these words:” functions exactly like using the Boolean AND.  So here if you were looking for someone named Wilson who lived in Davenport, you would enter Wilson Davenport.  The AND is not necessary. Thus the search of the index would return to you results for pages that include the word Wilson and the word Davenport anywhere on the same page.

The third box, “Any of these words:” functions exactly like using the Boolean OR.  So here if you were looking for someone named Wilson or someone named Willson (see the spelling difference?), you would enter Wilson Willson.  The OR is not necessary. Thus, the search of the index would return to you results for pages that include the word Wilson and pages that have the word Willson.  They do not have to be on the same page.

The fourth box, “None of these words:” functions exactly like using the Boolean NOT.  So here if you were looking for someone named Wilson who lived in Davenport, but was not named George, you would enter Wilson Davenport in the second box (All these words:), and George in the 4th box (None of these words:).  The NOT is not necessary. Thus, the search of the index would return to you results for pages that include the word Wilson and Davenport in them but would not return pages that have the word George in them.

There are various combinations that can be employed by entering a search string in multiple boxes, but that is for a later article.

So make use of Boolean searches in developing your search criteria. Whether you use AND or NOT to refine, or OR to provide more possibilities, these operators along with searching for phrases in double quotes will definitely improve the results that you get by leaps and bounds over just entering a name in a search box.