Apply for a job at Hilton International and three different computer systems have to approve your application before a human being will look at it. That’s the process Sarah Smart, vice president of global recruitment, outlines as she explains how the hotel chain uses artificial intelligence to weed out thousands applying for work in customer care:

First, an applicant tracking system searches people’s resumes for keywords matching the job description. Next, a chatbot asks them a series of yes or no questions to make sure they meet requirements, like, Do you have internet access for work-from-home positions? The ones who say yes get interviewed. But not by a person: This interview is with a predictive AI application called HireVue.

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Founded in 2004, the Salt Lake City company has raised more than $90 million in venture capital investment. “It’s a one-way interview,” says Smart. “The candidate will receive anywhere between five to seven questions that they get a chance to answer.” Hilton and HireVue develop these questions together, but they’re all designed to determine whether you’ll be a friendly worker, an empathetic one, and if you’ll be successful in the role. Applicants record their answers inside HireVue’s video platform, then the algorithm gets to work. It breaks down how many prepositions you use, and whether or not you smile. Chief technology officer Loren Larsen says the tool can examine around 25,000 different data points per video, breaking down your words, your voice, and your face.

“We have to start with what success looks like in the job,” Larsen says, explaining how each candidate’s analysis connects to individual work capability. Take customer service, he continues. “What are the competencies or skills or abilities or traits someone has to have to do well in that job? And then once you identify those, then you start to figure out, ‘Okay, let’s suppose friendliness is a trait.'” And when people are friendly, they smile, so that’s why the system studies candidates’ faces.

But should that smile–and how many times you show it–be what determines whether you get the job?

Hilton says yes. As Smart explains, “It’s a pass/fail.” Since becoming a HireVue client in 2014, 43,000 job seekers have interviewed with the algorithm. Two-thirds–roughly 28,667 people–had their applications rejected without being seen by a single person. (As hers is a corporate role, Smart herself did not go through the system.)

But according to Larsen, that’s not how the technology is really supposed to be used. As a company, he explains, “We’re never saying pass/fail. What we do return is a score that is essentially like your SAT score”–a percentile ranking of how each individual measures against others who applied at around the same time. Because so much data goes into compiling each analysis, no single smile or frown should keep you from getting work; it would just raise or lower your score by a few points. And only 10% to 30% of that score–depending on the employer–comes from facial expressions. The rest is based on the language you use.