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Trying to narrow down candidates for a role can be a difficult task for any recruiter. Using Boolean search writing can help you save time and improve the quality and specificity of candidates from the potential pool.
Boolean search is based on the work of prominent British mathematician George Boole. His legacy was Boolean logic, a theory of mathematics in which all variables are either “true” or “false”, or “on” or “off”. This logic still underpins all digital devices to this day, existing in almost every line of computer code.
Boolean search writing is a skill that top recruiters need to know in order to get meaningful candidate search results from a wide range of software, including LinkedIn, various job portals and Google. However, fully constructed Boolean search strings can look both confusing and complex, and may seem difficult to write. But never fear! We’re here to teach you some of the tricks of the trade.
What is Boolean Search?
Boolean Search uses a combination of keywords and the three main Boolean operators (AND, OR and NOT) to organise and sift through your searches. It produces more accurate and relevant results, allowing you to navigate through appropriate candidates, while disregarding the unrelated.
The first important thing to appreciate about Boolean is that there are only five elements of syntax to understand. These are:
By applying these appropriately, along with the keywords you wish to consider, you can create a huge range of search operations. There is no limit to how often you can use any of these elements in a search, so you can create very specific search strings, which will save you a lot of time in filtering the results.
The AND Operator
Take these two groups. In the first group are all the people who have the keyword “recruitment” somewhere in their LinkedIn profile and in the second, all those who have the keyword “HR”. But let’s see what happens when we use the following Boolean string:
Recruitment AND HR
We are now asking the LinkedIn database to search for all of the people who include both the word “Recruitment” and the word “HR” on their LinkedIn profile. We have filtered out the excess and are left with the more specific candidates who fall in the cross section of the Venn diagram.
The more criteria we add using the AND operator, the less people we will find with our search. It sounds like an oxymoron, but as we narrow our search using this method, we are finding the people who are most relevant for the position.
The OR Operator
In this example, one group of people have the keyword “Recruitment” in their LinkedIn profile, while the other have the keyword “Recruiting”. Both words mean the same thing in terms of a skillset, but to an electronic database, they are completely separate terms. Let’s use the following Boolean string to help rectify this:
Recruitment OR Recruiting
Now we are asking the database to search for candidates who include either of the two terms in their LinkedIn profile, or both terms simultaneously. It makes sure that the potential right candidate doesn’t fall through the net because of semantics!
Using OR broadens the search to encompass the entire Venn diagram. It enables us to find hidden talent e.g. people who have expressed their skills and experience in a different way than you might normally search e.g. banking OR bank OR finance OR financial.
The NOT Operator
The next example will help you narrow your search results by omitting unwanted criteria. Let’s take the first elements used again with “Recruitment” and “HR” keywords on a LinkedIn profile and use the following Boolean string:
Recruitment NOT HR
We are asking the database to search for candidates who have the word “Recruitment” in their profile, but to exclude any that also have the word “HR” in their profile and those who just have the word “HR” in their profile. This means we are looking to find candidates who fall just on the left-hand side of the Venn diagram:
Using NOT enables us to remove false positives from our candidate searches by eliminating irrelevant results.
REMEMBER: Each of the three above Boolean operators should always be written in UPPER CASE. If not, they will not work.
When using Boolean search, there is no way to determine how the computer will solve our equation. This means that in order to get the most relevant result for us, we have to use parentheses to tell the computer what to solve first. This is where using brackets comes into play.
Brackets are essential for writing complex search strings, but their application often causes the most confusion amongst recruiters. Essentially, a clause within brackets is given priority over other
elements around it. For example, if I was given the following search:
talent OR hr AND recruitment
Do I mean to say I want to find someone who has either the keyword “talent” or the keyword “HR” on their profile, and has the word “recruitment” too? Or do I mean that they have to have “talent” or the combination of “HR” and “recruitment”? You see, the absence of brackets makes it impossible for the database to know what you mean. Watch how things change when you add brackets.
In the following example, I have told the database that I need to find someone who has either “talent” or “HR” or both, and that they also need to have “recruitment”:
(talent OR hr) AND recruitment
But in the following example, I have told the database that I need to find someone who has “talent” or a combination of “recruitment” and “HR”:
talent OR (hr AND recruitment)
The most common place that brackets are applied by recruiters is in the use of OR strings. Basically, if you’ve written OR somewhere in your search, think about where the brackets will go because their
placement will affect how the computer solves your Boolean search query, which will affect search results you receive back.
The use of quotations allows for even more specificity. If the keywords you’re searching for need to be considered as a whole (e.g. gas engineer), then they must be enclosed within quotation marks in the search string. If not, the database will view the space between the two words as an AND, resulting in larger search that covers both words (gas AND engineer). Not ideal!
Use quotation marks whenever you have two or more words in a search that need to remain together like “Human Resources” or “Information Technology”. Quotations essentially define a number of words as one exact term, allowing you to pinpoint more accurately.
Today, we’ve explained the bread and butter of Boolean! We hope it helped you gain a better understanding of the fundamentals of Boolean search and made it less daunting to tackle in the future. There are, of course, several other Boolean modifiers you can use to further refine and improve your Boolean searches, as well as many more rules for the use of Boolean in various other search engines and databases beyond LinkedIn.