lexis nexis

Boolean Connectors

You can refine your search using “Boolean” connectors (named after mathematician George Boole), either to narrow your search to a more specific topic or broaden it to a wider subject area.

The three basic Boolean connectors are:

OR Connector

If you want to widen your search for documents that contain either of two words, use the OR connector between your keywords. Thus you might type:

homicide OR murder

This will retrieve all stories or documents in which either the word homicide or the word murder appears. The OR connector is particularly helpful in retrieving stories where the authors could have used only one of a couple of synonyms - such as homicide or murder – in a particular story and you want to make sure you retrieve all such stories no matter which synonym the author used.

Other examples of using the OR connector are:

environment OR ecology

doctor OR physician

Note: Boolean connectors can be typed in either in lower or upper case. I’m using upper case here only to highlight the connectors.

AND Connector

If you want to narrow your search to only documents that contain both your words, use the AND connector between your keywords. For example, you might type:

abortion AND protest

That will retrieve only stories in which both the word abortion and the word protest appear. In other words, stories more likely to be about abortion protests, not just about abortion.

You can also use the same connector more than once.

For example, if you want stories about protests about abortion where arrests were made, you might search for:

abortion AND protest AND arrest

Or if you were looking for stories with statistics on cancer, such as a report on whether cancer rates were increasing or decreasing, you might use the AND connector to string together words that probably would appear in such as story, such as:

cancer AND statistics AND report AND percent

AND NOT Connector

Finally, you can narrow your search to documents that contain one word, but not another, by using the AND NOT connector between your keywords. For example, you might type:

sharks AND NOT hockey

That will retrieve stories that contain the word sharks, but will exclude any stories that also contain the word hockey. Thus you’ll be more likely to get stories on sharks, the fish, than on the San Jose Sharks hockey team.

Other examples of using the AND NOT connector are:

49ers AND NOT football

(for stories about the 49er gold seekers but not the football team)

tiger AND NOT woods

(for stories about the animal, not about the golfer)

But because that latter string of search words would exclude stories about tigers living in the woods, an even better search might be:

tiger AND NOT golf