Applying for a job is a process filled with so many low points that when you come across a role that fits your skills and sounds interesting, it feels like a small victory before you even apply. But that feeling usually doesn’t last long, after days and eventually weeks have gone by and you still haven’t heard a peep from the company, not even a rejection.

Maybe a friend will try to console you by telling you that it was probably always going to be an internal job posting, but that they were obligated to post it. And while that may be the case, it’s also possible that the job posting, or even the role itself, never existed in the first place. Also known as “ghost jobs,” a recent study from Resume Builder found that 40% of companies have posted a fake job posting so far this year. Here’s how to spot fake job ads and why companies post them in the first place.

To be clear, when I say “ghost jobs,” I’m not talking about job postings that are actually scams designed to trick job seekers into paying money and/or giving away their personal information. (But if you’re looking for tips on how to spot them, you can find them in previous Lifehacker articles.) Instead, I’m focusing on job postings for nonexistent jobs at legitimate companies. Here’s how to spot them.

Sometimes companies will advertise jobs that don’t exist to gain a better understanding of the talent out there and to identify potential candidates in case there are actual positions to fill in the future. For this reason, ghost job listings are usually quite vague, both in terms of the specific qualifications they are looking for and the responsibilities that come with the position. When in doubt, contact the company’s HR department and ask for additional information about the position to determine if you are a good fit.