Sometimes this is due to a required confidentially of the search for new employee (i.e., a replacement for current job holder is required).
At times, posting the job would only result in receiving over a thousand resume submittals with only a small percentage actually being from qualified candidates. So, some companies prefer to seek out candidates through their own personal network where each candidate has been identified by a trusted source (this can lead to a high "hit rate" of successful hires for the process).
Other times, the need to fill a job hasn't been acknowledged, defined, approved, or budgeted. Then, a crisis happens (new client, new contract, etc.), the funds are finally budgeted, the "right" person appears, or some other event or circumstance changes and a new job becomes available.
Regardless of the reason, job seekers must realize this reality, and the best way to deal with the hidden job market is to leverage it. To do this, job seekers must be able to search for job openings that might exist or will exist, instead of do exist.
Where there’s smoke, there’s fire.
As you look at job openings at certain companies, realize there are likely more that are not listed. If they are hiring at all, that may signal there are other jobs either approved for hire or soon-to-be approved.
You should not apply for mismatched jobs to try and find others.
Instead, use the contact information to start your networking into the company. Through your own network, see who you can contact to ask about other opportunities that may be brewing at the company.
Connecting the dots with friends and neighbors.
Some job seekers keep their search secret. If you are leaving a company, that may be understandable.
But, if you’re currently unemployed, don’t let your pride get in the way. Another connection to the hidden job market is your friends and neighbors.
Like the job posting via personal network example above, you should be asking everyone you know, "Who’s hiring?" That is another way to start the investigative process you must employ to dive into the hidden jobs.
Seeing into the future.
Along the same lines, the request for informational or informal interview is a key tool for being considered for future opportunities. Many hiring managers love to keep their cache of great candidates as full as possible. Smart ones know that they can find great candidates if they look for them in advance of the need to hire. Timing is everything, as they say. These same managers also have connections to other hiring managers. You never know who they might connect you with.
You need to be bold about asking for an informational interview. You should offer to buy lunch or coffee to meet off-premises (which can be helpful for them in many ways). Be prepared to ask questions about what the company values for key experiences/attributes for the types of jobs you’re interested in. You should considering asking about how the manager got into their current position or where they’ve worked in the past. Ask about future hiring plans, too.
A company’s future hiring can occur during growth opportunities for the company. Keep an eye on their announcements. Key ones to watch for include: corporate moves or expansions, mergers and acquisitions, or new rounds of venture capital funding or awards.
Get into the company another way.
Another place hidden jobs exist is in contracting. Sometimes the best way to get a job is to contract for it first, prove your worth, and ask to be made permanent. Many companies solve current manpower issues by getting "temporary help" on board. You may look at this as only a band-aid to your current situation; however, there is no better way to finding a job than finding it from within the "company walls." Yes, it is a gamble that the job may not turn permanent or lead to other jobs at the company. But the odds of a positive outcome are much better than applying for dozens of jobs as an unknown quantity.
The good news about the hidden job market is that it is hidden. So this naturally means only the really dedicated job seekers are finding the opportunities. This translates to less competition for each job opening. Don’t overlook these. You might find getting a job through this method is a whole lot easier than putting your resume on the pile for a posted job.