If you are a sourcer or a recruiter who has experience creating Boolean search strings to search the Internet, LinkedIn, job board resume databases, and internal Applicant Tracking Systems, you may be familiar with the Boolean NOT operator. In my opinion, it's one of the most powerful and least utilized Boolean operators.

Most recruiting and staffing professionals use the NOT operator to exclude unwanted results from their searches. For example, when it comes to searching for resumes on the Internet, it is a commonly accepted best practice to exclude results that mention the word "resume" but are in fact job postings (e.g., AND NOT Job AND NOT jobs...).

However, the NOT operator can be used in a much more powerful manner than simply avoiding false positive results. The NOT operator can be leveraged to enable sourcers and recruiters to begin their Boolean searches by targeting ideal candidates first - candidates that meet all required and desired skills and experience requirements, and then systematically running successively looser searches using the NOT operator to remove one search term at a time.

In other words, the NOT operator can allow sourcers and recruiters to start their searches focused narrowly, and then loosen searches to make them broader. It also enables you to tap into the Hidden Talent Pool of candidates you don't find in every source of candidate data (Internet, Job boards, LinkedIn, ATS, etc.).

This Hidden Talent Pool is made up of the candidates that your searches return in the results, but you do not actually "find" them because your search returned "too many" results for you to review them entirely.

For example, if you run a Boolean search and it returns 398 results and you only review the first 100, you only looked through a small portion of the results, and thus you did not find the other 298 results. Any result returned by a search, but not reviewed by you is a candidate you did not find. This begs the question – how can you be certain that the best possible candidates are not within the 298 candidates you did not review? You can’t.

Simple, broad, and imprecise Boolean searches yield large quantities of imprecise results, and it is impractical for most people to sort through several hundred results.

So how can you specifically target the candidates most recruiters typically do not find?

Step 1: Your first search should always be a "sniper" search – very tight and narrow to quickly find and “cherry pick” a small number of highly qualified candidates.

For example, you can:

Add explicitly desired (but not required) skills and experience to your searches. These are typically listed on job descriptions and/or mentioned by the hiring manager

Add implicitly desired skills and experience to your searches. These are not specifically mentioned or requested anywhere, but would in fact make for a more ideal candidate. For example: industry-specific terminology, competitor-based experience, certifications, higher than minimum education, etc.

Add responsibility-related terminology listed in the job description to your searches

Add search terms to specifically find candidates who have performed the exact same time of work in the exact same type of environment as they would be if hired

Search a tighter geographical radius than you would otherwise. For example – if you would typically search in a 30 mile radius, start first by searching a 10-15 mile radius. It will narrow your results to a more manageable number and also solve a critical candidate variable – location/commute.

After running your first "sniper" search, systematically loosen your searches using the NOT operator to get mutually-exclusive results sets. The goal is to have a true search strategy, and why do anything other that start with the highest probability of match and systematically loosen the search on step at a time?

For example, let's say you are searching for a hiring profile with 3 required skills (A, B, C) and 2 desired skills (D, E). Let's also say that you decide to narrow your first search by adding a certification that is related to the work but not mentioned anywhere in the job order (F) and that you also decide to search for candidates with industry specific experience (G).

Your first search will look like this:
A and B and C and D and E and F and G

Your first search would be a “sniper search” to find any candidates available that meet all of the required, explicitly desired, and implicitly desired qualifications.

1. A and B and C and D and E and F and G

After "cherry picking" the best candidates available with that super-tight search, you can then run these searches back to back to systematically yield additional and mutually exclusive results – from highest probability of match to lowest probability of match:

2. A and B and C and D and E and F and not G
3. A and B and C and D and E and not F and G
4. A and B and C and D and not E and F and G
5. A and B and C and not D and E and F and G
6. A and B and C and D and E and not F and not G
7. A and B and C and D and not E and F and not G
8. A and B and C and not D and E and F and not G
9. A and B and C and D and not E and not F and G
10. A and B and C and not D and E and not F and G
11. A and B and C and not D and not E and F and G
12. A and B and C and not D and not E and not F and G
13. A and B and C and not D and not E and F and not G
14. A and B and C and not D and E and not F and not G
15. A and B and C and not D and not E and not F and not G

If you’re fortunate, you may find so many well qualified candidates from the first few searches that you may not need to run search #5, let alone search #15. The power of this approach is that you start by making the conscious decision to target the best possible candidates first, then systematically run searches using the NOT operator to peel away the layers, one at a time, to review manageable quantities of mutually exclusive results, with the last search performed being one that solely targets the minimum qualifications.

Essentially, this strategy starts with targeting the “maximum” qualifications. Most sourcers and recruiters run one search, maybe two, typically only searching for the minimum qualifications. Seems a little backwards, yes?

Sourcers and recruiters who run one or two broad and imprecise searches get a large number of broad and imprecise results – typically too many to review, automatically building the Hidden Talent Pool of candidates they don’t find. Also, broad and imprecise searches yield results in which each result has a low intrinsic probability of being the right match. It’s the difference between a shotgun and a sniper rifle – the goal should not be to be happy to just hit the target, but to hit the target in the bulls-eye with as few shots as possible. And the NOT operator can help you achieve this.