Boolean Basics – Part #1

NOTE #1: This is part #1 of a 2-part article.

Probably all genealogists have used Google for genealogy searches. For many of us, we go to, enter the name of an ancestor, click on SEARCH and hope that a reference appears that points to the person we wish to find. Sometimes the name search works well, and sometimes it doesn’t. When it doesn’t work, many genealogists give up and move on to something else. This is especially true with common names when a standard Google search may find hundreds of people with the same name. However, with just a little bit of effort, you may be able to quickly narrow the search to a single person or at least to a manageably small group of people. The trick here is to use some search terms defined more than 150 years ago.

George Boole

George Boole

150-year-old search terms? They didn’t have computers back then! True, but they did have mathematics, and computers are basically mathematical machines. Boolean algebra, as developed in 1854 by George Boole and described in his book, An Investigation of the Laws of Thought, is a variant of ordinary elementary algebra differing in its values, operations, and laws. Instead of the usual algebra of numbers, Boolean algebra is the algebra of truth values 0 and 1. In the case of computers, we usually think in terms of the logic statements of true or false. A zero is false and a one is true, as in, “This search result is a TRUE match to the terms entered.” Whether we use one and zero or true and false, all search engines work on Boolean algebra.

By applying a bit of Boolean algebra to our searches, we can be much more specific about the information we seek. We can specify not only the words we seek, but also how those words relate to each other. For genealogists, the results can sometimes be amazing. By specifying Boolean search terms on Google or other search engines, we can sometimes find ancestors or other topics of interest that have eluded us previously.

We can use search terms such as AND, OR, NOT, and NEAR as well as combining those terms with various characters such as quote marks, parentheses, and the minus sign.

NOTE #2: For the remainder of this article, I will discuss genealogy searches on Google. However, the techniques described here will work for searches for any sort of information, and the search terms described will work on most search engines and thousands of other web sites. However, there may be some minor differences on the non-Google services. On almost all search engines, the site’s Help files will explain the differences.

NOTE #3: For the remainder of this article, I will use a search for an elusive ancestor of mine: Washington Harvey Eastman. I chose him for two reasons: (1.) his three names provide an excellent example of the challenge of looking for ancestors on Google or other search engines, and (2.) I am hoping that someone else reading this article can provide more information about him! Actually, I know a lot about Washington Harvey Eastman. I know about his life, his wives, his children, the property he bought and sold, the taxes he paid, the livestock he raised, and more. However, I do not know his birthplace, nor do I know the names of his parents. Please let me know if you can help.

I performed a search on Google for:

Washington Harvey Eastman

Unfortunately, Google found more than 410,000 “hits!” That’s far too many for me to read. Just looking at the first few pages, I find many references to men who are not the one I seek. I find references to men named Harvey Eastman and to Washington Eastman and one reference to a man named Washington Gridley Eastman as well as a reference to a woman named Cheryl Harvey Eastman. Even further from my search purposes, one reference was to the Eastman Institute for Oral Health, referring to an employee who graduated from the University of Washington School of Dentistry. This is not the man I seek!

To be sure, each of these web pages did contain the three words I specified; so, Google did properly perform the task I gave it. Google found what I specified, even though most of the found pages were not what I wanted. After all, Google is a dumb computer: it does what you tell it to do which is not necessarily what you wanted to do. How can I narrow the search? I need some method of focusing the search to the results I seek. I can do that by using Boolean math.

AND: The first search term is AND. The Boolean term AND specifies that the words before and after the term AND must appear somewhere on the page.

When I specified a search for Washington Harvey Eastman, Google could have found pages that contain only two of the three search terms. However, I can require that all three words must be on the page by specifying a search of:

Washington AND Harvey AND Eastman

NOTE #4: Actually, Google always assumes AND unless you specify otherwise. This may not be true of all other search engines, however.

NOTE #5: Generally speaking, Google searches should use upper case for Boolean searches. In some cases, lower case will work, but this is not consistent. For instance, the search term of OR must always be entered in upper case while some other search terms will work in lower case. In order to reduce confusion and to always obtain the results you seek, I suggest you always use upper case for Boolean search terms. However, either upper or lower case may be used for the other words in the search string, such as WASHINGTON harvey eAsTmAn.

OR: While not as useful in my simple search, the Boolean term OR indicates that either word or text string will be found. The OR command is very powerful for use in genealogy where name spelling variations are common. The OR command states that you are looking for multiple spellings or names. For instance:

Eastman OR Eastmen OR Easman

The above search states that any of the three spellings are acceptable.

I will show more powerful uses of the OR command when combined with parenthesis later in this article.

NOT: A much more useful search tool is the use of a NOT command, meaning the following word should NOT appear in the search results. Google uses a dash, or minus sign, to specify NOT. For instance, any search for a person named Eastman will probably find references to a large photography company in Rochester, New York. Those pages can be easily filtered out by using the NOT command:

The following search will significantly reduce the “false hits” that lead to pages concerning photography:

Washington Harvey Eastman Kodak

Notice that the dash precedes the search term with no space between the dash and the next word.

You can also chain together several minus sign commands on the search line. For instance, to reduce the number of pages found about photography while also reducing the number of pages found that refer to Washington, I normally use this search:

Washington Harvey Eastman -Kodak -George -DC

This search states that neither the word “Kodak” nor the letters “DC” should appear on any page listed in the search results. I also do not want the word “George” to appear in the results as George Eastman was the founder of Kodak and his name appears often in pages I do not need to see. The NOT command and most other Boolean search terms are very powerful, partly because they are literal: they will do exactly what you stated, even if it is not what you intended.

The answer is easy, however: perform multiple searches, both with and without the NOT command.

PARENTHESES can be used to build complex searches that will quickly find pages of interest. For instance, I might know that my ancestor lived in two different towns and I want to find references to him in either place. I might construct the following search:

(Eastman AND Corinth AND Maine) OR (Eastman AND Bangor AND Maine)

This example will search for any references to the name Eastman in either Bangor or in nearby Corinth, Maine. It will ignore any references to Corinth, Mississippi, or to Bangor in Gwynedd, a county in north-west Wales. Google will begin by searching for all matches that are specified inside the first set of parentheses, and then it will search for all matches that are specified inside the second set of parentheses. It displays all the results at once.

In Part #2 of this article, I will explain some of the more advanced Boolean search terms. I will also add in a few non-Boolean terms that are specific to Google and may help narrow your searches even more effectively. I will also show you a much easier method of using Boolean searches on Google without having to manually enter all these cryptic commands!


Really cool, Dick!


Wow! You’ve open a whole new world for researching on Google. Gotta love Booleans.


Finally, I may find what I am looking for – Thank you very much,Dick!!:}


Google searches are a great source for genealogy. I have used a simple ‘marriage’ search on all my married couples [his name, her name + the word ‘genealogy’ ] and found about 90% high degree of quick results, and in places/resources I would never have found otherwise. First I exported a list of Marriages (report) from my genealogy software to a text file with just his/her names, and from that text file, just a copy-paste of the double his/her names plus the word “genealogy” into the google search box. The lookup of the list goes very quickly; I saved the first two pages of google results into MacJournal (could be into any xxx.rtf file if you want to save the ‘live’ links to pursue later the actual lookup detail later, one by one). In one or two evenings you have hundreds of new lookup sources to pursue. Also the summary ‘number of hits’ at the top of the google search gives you an idea of how hard/easy it is to find that couple in all the info out there; and whether you need to add more info to the search box (dates, places, etc).
For those looking for more advanced info on google searches, these following resources are very detailed and helpful:
I ran across this Youtube video series which I thought was very helpful 
It is “The Google Genealogist” Devin Ashby – he has a series of 5 of these videos, plus three others (maps, and ‘your family history’ [clip from a class] +tips &tricks) – all are good for exploring Google’s power for specialized searching, etc.   Reference to pictures were on #4.

a link to #1 of the 5-series is

On my viewing, the others 2-5 played following that in a playlist. The 3 others I found from his own Youtube site:  

Others 2-5 of series (I think I have these right) 





Tips & Tricks   (low volume)


Thank you, Dick, and Edmund Deane. You both have given me my homework assignment for the foreseeable future.


(Eastman AND Maine) AND (Corinth OR Bangor) is shorter and accomplishes the same thing.


I entered into DuckDuckGo (not Google) as follows: “Washington Harvey Eastman” — I always use parens so the search is narrowed to the entire name and not just one of the names. It gave me this: b. 3 Apr 1810 in Civil, Corinth, Penobscot, ME. I haven’t any idea what this “Civil” means, I’ve never seen it before.


Thank you so much for refreshing my memory about Boolean searches. I had forgotten some of this since my teaching days. Now I can go back and redo some searches, hopefully, with better results.


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