News studio interview on personality testing with Eliza Gray. Headers of various magazines about personality testing are shown.

REPORTER 1: Many companies now believe personality testing is best to measure applicants friendliness, curiosity, and independence. Not everyone agrees. The cover story of Time magazine this week takes a close look at the trend. The story is by Times staff writer, Eliza Gray, who joins us with more. Good morning, Eliza.

ELIZA: Hi, good morning.

REPORTER 1: So, it's interesting. More than 450 of the top Fortune 500 companies are now using this kind of personality testing. What insights are these employers gaining?

ELIZA: You know, they're learning is-- what they're looking for is a fit for a job, so, you know, you can imagine, you might want a different kind of person to be a Wall Street trader than to be a nurse in a neonatal unit, right? But, you know, a lot of what they're really looking for is correlations to their bottom line. If you're a call center employer, and you look at your best applicants-- I mean your best employees and look at their traits, you can measure them against the people who are applying for the job and say this correlates to lower turnover and higher success, let's use this data and get these people in here.

The text on the screen states that according to Wall Street journal 57% of large employers tested applicants in 2013, that increased from 26% in 2001 and according to Time magazine the results of testing for personality traits that will lead to success in particular role.

REPORTER 2: This isn't just being used for executives now, it's being used sort of across the board right.

The text on the screen states that according to Business Insider the reasons for using personality tests are as follows. First, they erase the ‘know it all’ mindset. Second, they are used for extremely new positions. Third, they are used to find a good fit for the team. Fourth, they are applied to know if new skills can be learned. And last, they are used to understand if a well-balanced team can be achieved.

REPORTER 2: Obviously, employers are convinced now that these tests actually work and reveal the trends they're looking for.

The text on the screen shows a set of personality test statements that the person should answer True or False. The first statement is that I follow my instincts wherever they lead me. Second statement is that planning is one of my best abilities. Third statement is that my friends would describe me as impulsive.

ELIZA: Sure. I mean, what the tests do, often, I would say is for turnover, and sometimes even in sales numbers. Like, they can show-- at Jetblue, for example-- that if you fit their personality profile to a T, customers are 15% to 25% more likely to compliment that particular employee. So they're seeing real benefits from it. It's sort of a legacy of our big data obsession. You know, this idea that you can collect all this data about someone and you can use it to make predictions about how they're going to do.

Video provided by BBC Worldwide Learning.

YOSSEF S. BEN-PORATH: The MMPI-2-RF is used in public safety settings, primarily in pre-employment evaluations, although it can also be used in fitness for duty assessments. In pre-employment evaluations, one of the challenges when using the MMPI-2-RF is that we're not dealing with the clinical population. Instead, we're dealing with a highly pre-selected population, because in order to even be referred for a pre-employment evaluation for, say, law enforcement or other public safety positions, you need already to have been offered the job. You need to have been given a conditional offer of employment. That's part of the requirement of the requirements of the Americans with Disabilities Act.

So, we wind up seeing a psychologically healthy population, by and large, when doing these pre-employment evaluations. We shouldn't expect to, nor will we find, many clinically significant elevations on the MMPI-2-RF. Fortunately, we have a very solid and comprehensive body of research that helps guide use of the tests in these settings.

And this research has indicated that non-elevated, not clinically elevated, but still significantly above the norm for, say, police candidate scores on the MMPI-2-RF are associated with negative outcomes in police candidates. And we can rely on this literature to help use the test as part of the pre-employment evaluation for identifying risk factors associated with hiring a given candidate.