Hiring managers often tell me they want to hire someone with “passion.” They believe that passionate people will be more self-directed, more motivated to learn new things, and more likely stick around for the long haul, and not just quit when times get tough.

And truly passionate people will do that.

But far too many hiring managers don’t recognize passion when they see it.

Passion takes many forms. One kind of passion is easy to spot in an interview. It’s the instant-on enthusiasm and charm of an extrovert. They are fun to talk with, everything seems exciting, and you feel uplifted in their presence … like anything is possible. CEOs are often drawn to this kind of person because of their ability to “rally the troops.” But this kind of enthusiasm can also wane very quickly. Hiring for enthusiasm is selecting style over substance.

Why are we so deceived by enthusiastic, charismatic candidates? Because we’re enamored by enthusiasm. A professor decided to test this with his college class; doing everything he could to ensure the fall and spring semesters of his course were essentially identical – same office hours, same slides, even memorizing his lectures so they’d be identical. The one thing he changed was his enthusiasm. In the spring semester, according to Matthew Hertenstein author of The Tell: The Little Clues That Reveal Big Truths about Who We Are:

Students exposed to Ceci’s enthusiastic presentations were much more positive about both the instructor and the course— even though everything else was identical. They perceived him as more enthusiastic and knowledgeable, more tolerant of others’ views, more accessible to students, and more organized… The students in the spring semester also reported that the course goals, expectations, and grading policy were more clearly stated and that the grading was more fair. They even rated the identical textbook more positively in the spring.

Just his level of enthusiasm was enough to convince his students that their textbook was better. So clearly enthusiasm has value.

But enthusiasm alone is rarely enough to get results in the real world. Ideas are a dime a dozen. And if your new hire is all charm and style, they might bail out when the going gets tough … and let’s face it, the going always gets tough.

When the stakes are high and the chips are down, relentless disciplined execution is what delivers results. To understand that in an interview, you must look beyond a candidate’s superficial charm, and instead focus on the harder-to-identify resilience, persistence, and determination. Truly passionate employees are the ones who show grit. Because everything, including a great idea, looks like a failure in the middle. And if a candidate doesn’t have the grit and determination to deliver the goods through that hopeless middle of a project, they will be gone before the end …and you’ll be left holding the bag.

Grit and charisma are not mutually exclusive – some people are both determined and charming. But your charisma is much easier to identify in an interview. To hire grit, you must recognize that your ideal candidate might be a misfit toy. They might even be a bit awkward during the interview. They may not invest much attention in their charm, but once you get them talking about projects and metrics and obstacles overcome and you will see them light up.

If you’d like to stop wasting your time on the irrelevant, superficial aspects of interviewing, and start understanding the deeper elements of what really predicts success a new hire, read our post on How to Conduct a Job Interview so Top Performers Actually Want to Take Your Job.  And, if you prefer all that research and information pulled together into one attractive document you can easily share with others, download our Employer Guide to Interviewing.

This article originally appeared in the HR Examiner