Boolean* searching can be very beneficial in enhancing the quality and accuracy of your genealogical
searches. By definition, a Boolean search is a technique where you can use special words or symbols
to limit, widen, or better define your search. Following the options below you can achieve results that
are more productive and better focused than simple keyword queries. This refinement is made using
logical operators such as AND, NOT, and OR and symbols like + (add) or – (subtract) to your keyword
searches. These operators can also be stacked or repeated multiple times within a single search.
When you include a Boolean operator into your plain-language search query, you're introducing
flexibility to get a wider range of useful results and you may also be identifying limits to reduce the
number of unwanted results. Here are three examples.
AND (+) The Boolean operator AND tells a search engine you want to find information about two (or more) search terms. For example, cats and dogs or the names Smith and Jones. This will narrow your search results because the search engine will only bring back results that include both search terms. If you know at least two facts about your search subject, place this Boolean operator between them!
NOT (-) The Boolean operator NOT tells the search engine you want to find information about the first search term (to the left of the operator), but nothing about the second (to the right). For example, “cats NOT dogs,” or all combinations of “Smith,” but “NOT John Smith.” This will narrow our research results because the search engine will bring back only resources about the first search term (cats, or the name Smith), and will exclude any resources that include the second search term (dogs or John Smith). This is helpful when you get too many unwanted results in your first search attempt.
OR The Boolean operator OR tells the search engine you want to find information about either search term you have entered. For example, “dog or puppies” or combinations of the names “Smith” or “John.” This will broaden your search results because the search engine will bring back any results that have either search term in them.
Boolean searching can be used to find relevant results from library catalogs, databases, and the world wide web. Boolean Operators can expand, refine, and improve your searches. Some of the other useful Boolean modifiers include the asterisk * for truncation and wildcard searches, parentheses (-) and quotation marks “-”. Here are some additional tips for using these Boolean operators.
Asterisk * attaches to the stem of a word and searches for any word which includes that stem, or any sequence of letters before the asterisk. Therefore, you will get results with different endings but all the same stem or sequence. See the following example: Searching for stat* will return expanded results with the following words: state, states, statute, statutory, statistic, statistics, stats, statistical, and more! The most powerful thing about this operator is that it can be used anywhere within a sequence of letters: the beginning, middle, or end and the asterisk can represent any number of letters. Think of how useful this will be in dealing with the many spelling variations in ancestors’ names!
Parentheses, (-), are used to encapsulate OR statements. This can create a compound proposition combining the effects of two different Boolean Operators. Use parentheses to specify the order in which the operators are interpreted by enclosing your search terms in parentheses. For example, “(heart OR lung) AND bypass” will return different results than “heart OR lung AND bypass”. In the first example, the parentheses modify the OR operator to mean “either”; whereas in the second example (without the parentheses) the OR operator means “any.” If you want results that return only one word out of a group of two or more, put them between parentheses to ensure that only one of the search terms is returned: (elderly OR aged OR senior citizen). Yes, you can create statements that stack as many multiple terms (joined by OR) as you need to encompass all the details of your search!
Quotation marks, “-”, return exactly what you typed inside the quotation marks. If you search for “state” (using quotation marks) you will only get results containing the word “state,” so the plural "states” and the word “statesman” will not be included in your search results. Use this operator to improve the focus of your results!
Use truncation to obtain results that include multiple variations of a word by adding an asterisk at the end of the truncated word. For example, searching for “laugh*” will return results that include “laugh,” “laughing,” and “laughter.”
For more information on this topic, I suggest visiting the following Internet links.