Is Personality the Ultimate Solution to Hiring?

There are hosts of personality tests on the market, all claiming to be helpful in making hiring decisions. But before hiring and recruiting professionals commit to using personality tests, they need to understand the difference between “causation” and “correlation.” In other words, does a “good” personality score really indicate “good” performance? Causation means that one thing causes another to happen. Spit on Superman’s cape and you can expect to be punished. The stimulus causes the punishment. Correlation is different. Correlation means that two things tend to occur at the same time, but one does not “cause” the other. Blue hair and Grandmas are correlated (i.e., co-related), but having blue hair does not cause someone to be a Grandma. This is a very important thing to know (as we will see later) when using a personality test to hire someone.


Why do we give applicants tests? To quickly predict future performance! That is, instead of hiring someone and then waiting around a few years, we give applicants a short test, examine the score and conclude, “A-ha! This score means our applicant will be our next _____!” Test results, however, are accurate only if the test content is associated with job performance, meaning that it has a causal link to on-the-job behavior. For example, it’s “causal” when employees with bad problem-solving skills make bad decisions. It’s “causal” for bad decisions to create unnecessary expense. Therefore, common sense tells us that when problem solving is important to job performance, a quickie test of problem-solving ability can lead to more profits and fewer mistakes. A problem-solving test will simulate problem-solving on the job, and when properly validated, will show that low test scores predict low job performance. But what about personality tests? What do they have to do with job performance? (Note: I use the term “personality test” to mean any kind of self-descriptive test of style, temperament, or interest). Week after week, I see people using scores from personality-type tests to predict job success. When I ask them about causation, they look as me as if I just arrived from another planet. Then, after a long pause, I usually get three kinds or responses:

  1. “Our managers like it. That’s good enough for us!”
  2. “We gave it to our top producers and use their scores as our answer key.”
  3. “Huh?”

Sigh! Where is Superman when you really need him? We will only examine responses along the lines of #2 above. #1 and #3 buyers deserve what they get.

What’s a Top Producer?

This is one of those situations where common sense fails us. The term “top producers” is an attractive one, but top producers are seldom alike. For one thing, what is the definition of the word “top”? Most popular? Most sales? Most repeat customers? Biggest projects? Best attendance? Best looking? Lowest golf handicap? People are generally good at some things and poor at others. Lumping all “top producers” into the same category is like putting mixed fruit into a blender and pressing the “liquefy” button. All the individual differences disappear into mush. Therefore, the first step in using personality to predict job performance is to avoid the blender approach and carefully define the term “top” — for example: “most friendly,” “most service-oriented,” “best closer,” “best cross-dresser” (sorry, make that “cross-seller”). Remember, the more explicit the performance criteria, the more accurate the study. Some readers may now be thinking, “This is tough. How can I possibly classify top producers into similar groups?” Congratulations! They have moved one step closer to hiring enlightenment.

The Problem With Averages

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Okay, we have minimized the blender approach and properly classified producers into a variety of “top” and “bottom” groups. Now we can give all top and bottom producers the personality test, average each group’s scores, and compare the differences? We are done, right? Not by a long shot. Averaging individual scores is like having one foot in a roaring hot fire and the other in freezing ice water, and concluding, on the average, that the temperature is comfortable. “Average” comparisons might seem like a good idea, but they tend to conceal extremes. Here’s an example. Take two score-ranges for adaptability: The high group had a range of 50 to 90, with an average of 70; the low group had a range of 40 to 80, with an average of 60. There’s a difference! We can use it to predict individual performance! Right? Wrong. Yes, there is a difference based on groups. But what we care about is hiring individuals, and there is an inconvenient score “overlap” that needs explanation. Why do some individuals in the “low group” actually score higher than the “high group,” and vice versa? We discovered correlational group differences for adaptability, but we cannot conclude adaptability causes performance.

The Right Way and the Wrong Way

When we “shotgun” a personality test to employees (i.e., give everyone the test and look for patterns), we run the risk of finding garbage relationships. That is, we might find high scores in “adaptability” are common among high performers, but that might occur entirely by chance. Could shotgun studies lead to hiring mistakes? Remember the blue-haired Grandma example? Shotgun personality results showed that blue hair and Grandmas were correlated, so if we started hiring only applicants with blue hair, would we get the Grandmas we needed? In other words, will blue-hair cause someone to become a Grandma? No, although we made blue hair a hiring criterion, some would be Grandmas, some punks, some Goths, and some men. Blue-haired was a bad hiring criterion because it did not “cause” Grandmas. Likewise, although “adaptability” might be common among high performers, will hiring applicants based on high adaptability scores lead to skilled employees? How do we discover if high “adaptability” actually leads to high performance? It’s a multiple-step process.

  1. We start with a clean slate.
  2. We interview jobholders, managers, and visionaries, asking them all kinds of questions about success and failure, listening carefully for key behaviors that sound like “adaptability.”
  3. We carefully separate existing employees based on some form of “adaptability” rating.
  4. We give both high and low performers a valid and reliable personality test (i.e., one specifically designed to measure on-the-job adaptability).
  5. We statistically compare scores on the adaptability test with adaptability performance ratings.
  6. If high adaptability scores correlate with high performance and low scores with low performance, then we can feel confident our adaptability test will predict job performance.

The Research

What’s a good article without research to back it up? The research shows:

  • Personality is only a good predictive factor when applicants already have the skills for the job. Think of skills and personality as two sides of a coin: One side represents the “hard skills” brought to the job (“can do”), the other, personality, represents how skills are applied (“will do”).
  • There are only a few personality traits associated with job performance. The challenge is to find and confirm them.
  • When done right, and assuming the employee has the right “hard skills,” having the right personality for the job can affect productivity by at least two to one.


7 Comments on “Is Personality the Ultimate Solution to Hiring?

  1. It’s not the ultimate solution, but I prefer hiring individuals who don’t bore me in an interview. I move those individuals to the bottom of the list.

  2. In regards to personality test how many times have you heard the statement ‘Oh I really like so and so but they are really hopeless at their job.’ This is especially problematic when hiring for jobs that require a lot of personal interaction (sales, HR). While you need someone who is a good communicator that can interact with clients (internal and external); if they aren’t communicating the details of the job they are useless.

  3. I have been in the business for many years and have found that for key posts and higher level positions, Personality is definitely the key, although this is also especially true for lower paying positions such as a Receptionist or an Admin. Receptionists are the front line into a company and Admins are the pivot around which HR revolves. They need to have strong but very pleasant, likeable and blendable personalities.

    I took a course in Neurolinguistics years ago and learned quickly to my advantage, that skills can be learned but if one does not interact well with your interviewer, especially during the job interview, then it is unlikely to happen. That is also why many companies utilize group interviews to get accurate feedback.

    I coach many applicants to mirror image their interviewers. I counsel them how to dress, wear their hair, what colors to wear, how to conduct themselves at a lunch interview, how to shake hands, how to be remembered in a memorable way. I once took off my jacket and loaned it to a Director who came without one for an interview. I was much shorter than the candidate, so I asked her to bend her arms while she was there because the sleeves were short. I have to honestly say that the jacket closed the deal.

    Every company hires because they want an asset, someone who can be an ambassador for their company to the public. Tecchies do not need it as much, but Personality is surely the key!

  4. I agree with Dr. Williams on several counts: the inappropriateness of correaltion scores for showing cause-effect; the fallacy of averaging scores as a way to discriminate high performance criteria (which also means the fallacy of using norms); and the need to assess both high and low performers.

    That said, I’m not sure what he means by ‘personality’ other than that it’s different from ‘problem solving.’

    WE have found that the discriminators between high and low performers are company specific. What can be managed as a trait in one company cannot necessarily be managed in another. For example, we found high performers in one sales group were distinguished by a low level of confidence and a high level of unconventional practical problem solving ability. We found in another sales group the high performers were distinguished by a high level of conventional, structured thinking and problem-solving ability.

    Moreoever, we found this not by asking the persons to describe themselves but by using a simple decision science test that is highly validated, using axiometric measurement (axios = valuing or choosing). We’re finding we can indeed discriminate high performers from low performers quickly and easily, using job-based performance criteria and measuring talent using axiometrics.

    It seems to me that job performance is all about decisions, minute and gross. Thus it makes sense to measure decision talent rather than a person’s alleged self perception, if we really want to accurately reach the ideals so well espoused by Williams. I notice his assessments instead use self-report.

    I’d be interested in what others think. Do you agree that self-report instruments limit our ability to accurately assess?

  5. Our correlations between ‘personality’ scores and ‘skills’ ranges between 1% and 10% of the variance (statistical psychobabble). That means a high score in self-described ‘problem solving trait’ or ‘teamwork trait’ only has about a 1% relationship with scores on a hard-to-fake mental ability test or perfomance in a hard-to-fake one-on-one simulation.

    I wrote extensively on this in an earlier ERE article (see: ‘Einstein-Clavin Effect’)

    There is a wide gulf between a business understanding of personality and an academic one. Business-related personality is better termed ‘work-related attitudes, interests and motivations’. It is the subjective ‘stuff’ that influences the application of individual skills and behaviors…it is not a ‘skill’.

    ‘Self-report’ refers to any system, written or otherwise, where people are asked to describe themselves, their values or motivations. Even a value-choice format represents an unverifiable self-report.

    We tend to think personaity test scores are like the bathroom scale…i.e., that it represents an absolute value directly related to the number of ‘love handles’ around our middle. Experts in the field know otherwise.

    The numbers on a ‘personality-test’ represent a self image… how we want others to perceive us…this is a far cry from a trustworthy gold-standard.

    By the way, there is a large body of research showing a comparative-choice test format may tell us a great deal about each other, but not about a job standard. Anyone can read them by doing a search on ipsative-scored validation studies.

    Can personality be faked? I think Jo said it best when he said he could coach applicants to ‘pass’ the interview personality ‘test’. I wonder how many employers question how the ‘nicely-behaved applicant’ could turn into the ’employee from hell’ a few months later?

    Debbie mentioned being a good sales communicator. I could not agree more, but this skillset is best evaluated by a simulation. I have many clients who liked (i.e., were sold) a candidate, but quickly chaged their minds when they heard their performance in a sales simulation.

    Ibby mentioned being bored in an interview. Again, I could not agree more. But my article was not about being boring…it was about matching personality to job requirements.

    We don’t make this stuff up folks. Like it or not, these comments reflect academic research on hiring and testing.

  6. Hi:

    Probably the best objective insight regrarding the validity of individual selection tools, as well as their validity when used in conjunction with each other, was extensively described in one of Lou Adler’s recent articles–‘The Search for the Perfect Candidate, Part 4.’ This insight comes from a Psychological Bulletin article entitled ‘The Validity and Utility of Selection Methods in Personnel Psychology: Practical and Theoretical Implications of 85 Year of Research Findings.’

    Bottom line, the article concludes that of all the selection measures reviewed, two combinations standout as the most practical and valid tools: 1. Pairing a mental ability test with an integrity test (a.k.a.-personality test) and 2. Pairing a mental ability test with a structured interview. Note, both approaches include self-report measures (integrity test, structured interview). Interestingly, two other composite predictors fell within a similar validity range: 1. A mental ability test and a work sample test and 2. A mental ability test and a conscientiousness test (self-report personality).

    Certainly applicant faking can impact the validity of self-report selection measures?just like guessing can impact other measures (e.g., tests of knowledge, assessment center exercises, mental ability tests, job simulations). However, this hardly means that these instruments do not exhibit validity. Rather, the validity coefficients in the study referenced by Lou Adler would probably have been even greater if faking could be totally controlled.

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