Are personality tests reliable? All you need to know

Are personality tests reliable? All you need to know

Although measuring personalities is no easy task, valid personality tests are great tools for gaining a deeper perspective into a person’s psyche. Typically, these kinds of tests use questionnaires to measure personality traits, motivations, and behaviors; that is, among other things. That’s why we use them widely in the hiring process. Besides, ensuring that the chosen candidate fits the company’s culture — and needs — is of utmost importance, for everyone’s success. 

Be that as it may, how reliable and accurate are personality assessments? Can they really help HR professionals and hiring managers to choose the right employee for a company? If so, how?

Are personality tests reliable and valid?

There are some who believe that personality tests are lacking, mostly because personality is subjective and tends to change, over time; at least, some more fluid aspects of it. Nonetheless, personality assessments have stood the test of time, and have been providing valuable perspectives and insights, regarding job applicants, for decades now. 

In fact, personality tests are becoming increasingly popular, especially in professional settings; and, though some people might question whether a personality test is accurate or not, ongoing studies are being conducted to test their reliability, and ensure their accuracy. 

Tests based on the Big-Five (OCEAN) or the HEXACO model measure scientifically defined personality factors — such as extraversion, agreeableness, conscientiousness, etc. — to assort people into specific personality types. By grouping candidates in such a manner, recruiters can gain insights into basic aspects of their personalities.

So, are personality tests reliable? Yes, there are many personality tests that are reliable, and they also provide valid information; hence, helping make sound HR decisions, most of the time. However, when in the process of choosing a personality test, it’s important to research the reliability of the potential test provider; they should be able to guarantee for the most accurate and scientifically backed data. 

What proves the reliability and validity of personality tests?

There are, indeed, tests — some, among the most famous ones — that have received criticism on their validity. But people always have different perspectives on matters such as these; and, probably, always will. To explain, while some may be skeptical of categorizing individuals into defined personalities, others claim that personality classification can provide valuable insights. 

Still, especially in the workplace, personality assessments can minimize the risk of placing candidates in the wrong role; and, at the same time, provide employers with analytics on what motivates and inspires their existing employees. 

So, where does one look for proof of the reliability and validity of personality tests? Without a doubt, proof comes from science; and the data it provides from extensive scientific research.

Personality tests through the lens of science and scientific research

Now, as mentioned, we often research and study the reliability and validity of personality tests using new, more advanced methods every time. Personality tests have been around for many years; and have consistently provided psychologists and HR professionals with deeper insights into test-takers’ personalities and behaviors.  

At this point, we should distinguish between reliability and validity, as they’re not one and the same; not if we are to better understand this subject from a scientific point of view. When researchers record scores of the tested individuals with consistency, then reliability is verified. On the other hand, we can prove Validity when the test fulfills its function; that is, when it measures what it claims to measure. 

We should also note that, since personality is hard to measure — so, there are also other factors at play — such tests are more reliable when taken more than once. 

Reliability of personality tests in the workplace

We’ve clarified, so far, that personality tests are a great way to assess a candidate’s potential cultural fit. Such assessments measure different personality aspects that are deemed necessary for specific job roles; therefore, hiring managers use them to increase the chances for a successful hire. However, we should keep in mind that they bring better results when used in conjunction with other hiring methods and tools; such as resume checking, face-to-face interviews, aptitude psychometric assessments, etc. 

That being the case, HR specialists and hiring managers need to understand both the advantages and disadvantages of personality assessments, in order to make informed decisions. To that end, we’ve listed below some of the pros and cons of using personality tests in the hiring process.

Pros, in hiring

1. Preparing for the interview

Putting together the right set of questions, for an interview with a candidate, is a time-consuming task; at least, if done properly. A personality test before the screening — which is always recommended — can greatly help in that direction. As a matter of fact, the whole interview can be based on information obtained through the test. To elaborate, the assessment can help hiring managers personalize the interview, and focus on certain questions, built around the candidate’s answers.

2. Speeding up the hiring process

Utilizing personality tests as a pre-screening tool can, undoubtedly, narrow down on candidates that best fit the role; hence, that are more likely to move forward in the hiring funnel. In effect, this can significantly expedite the recruitment process, speeding up the time it takes to make a hire.

3. Gaining deep insights into a candidate’s potential personality traits, motivations and behaviors

A personality test helps HRs and managers to gain deeper insights into a candidate’s potential personality traits. Drawing from the test results, they can grasp whether a candidate possesses the personality traits and soft skills required to align with the current job demands and company’s needs. 

What’s more, we can also use personality assessments to measure a candidate’s preferred mode of learning, how they respond to tight deadlines or changes, etc. Recruiting managers can also determine what job roles will keep a candidate engaged, motivated, and productive. Conversely, they can determine what job roles — or job-related activities — may burn them out; or, even, bore them out. We can effectively utilize all these insights to make the right hiring decisions; and can prove key for building and maintaining a successful team, in the long run.

4. Pinpointing vocation-specific traits

We all know that not all jobs require the same personality traits. The good news is that personality tests are flexible enough to be customized to different job roles and requirements; while maintaining their reliability and validity. Vocation-specific tests exponentially increase the possibility of hiring the right person for a job. For instance, an extroverted candidate personality may be a good fit for customer care or a sales role; however, the same skill is not important for a software developer, and so forth. 

5. Saving time and money

All the aforementioned points can attest to the fact that personality tests can be implemented relatively easily; and that they are a value-for-money investment, for any company. A scientifically reliable and valid personality test provides information about a candidate within hours; which may take several days, or weeks — or months — for an HR manager or a hiring manager to ascertain on their own, without a solid, normalized set of data.

That said, these tests can reduce — in many cases, even eliminate —  the chance of a bad hire, providing a good return on investment (ROI). As most HR professionals know, a bad hire is not just a costly investment; but can also significantly encumber the productivity — and morale —  of other employees.

Cons, in hiring

1. Candidates may not be honest with their answers

It’s not very rare for candidates to answer in a way they think their potential employer wants them to, when taking a personality test. In other cases, they may not pay attention to the questions when answering. Sometimes, when a candidate takes a personality test, their emotional state also may be very different from the state it would usually be in the work environment. 

For all these reasons — and more — their personality test scores might produce inaccurate results. As a result, recruiters might end up filtering out good candidates from the hiring process; and, end up hiring the wrong candidate for the position.

2. Personality tests may not be 100% accurate

As we’ve mentioned, personality tests cannot possibly be absolutely accurate. Nevertheless, their accuracy is mainly jeopardized by dishonest answers or uncustomized questionnaires that don’t fit a particular job role; in which cases, there may be discrepancies in the accuracy of the results. To avoid this, hiring managers may want to have candidates take the test more than once. And, by all means, ensure they’re using a reliable and valid personality test, from a trusted provider.

3. Once in a while, recruiters need to trust their instincts

At times, HR professionals and managers are forced to hire an individual instinctively, based on a hunch or “good vibe”. That especially happens when two or more candidates seem to be a good fit for the job role on offer — based on their test results. After all, there are things that science, and data cannot measure; often, first impressions do matter. If anything, a personality test should always be just one of many tools and processes used in hiring.

What to avoid, to make personality tests more reliable when hiring

Even though there are many advantages to using personality tests, there are a few disadvantages too. Notwithstanding, HR professionals and hiring managers can use these tests to the company’s advantage, if they’re careful not to fall into certain pitfalls. That goes to say, there are a few things they should avoid when using personality tests in the hiring process, to make more reliable hiring decisions. So, here’s what to avoid when using personality tests for hiring:

  • Run personality testing after the interview stage
  • Base a hiring decision solely on the results of a personality test
  • Select a personality test from an unknown provider without some research first, just because of the price
  • Make biased decisions — towards or against sex, sexual orientation, nationality, religion, age, etc.
  • Opt to hire a particular personality type, based on existing employees

Any one of these may exclude top candidates or lead to an unsuccessful hire; costing the company time and money. 


While personality tests shouldn’t be the only tool to use for hiring decisions, utilizing them to supplement other hiring tools and processes is an excellent way to analyze candidates in-depth. Regardless of not being 100% accurate, they’re a great solution for improving hiring decisions; and, ensuring that the right people are hired for the right job roles. 

By all means, the insights such tests provide can help hiring managers better understand both potential employees and current employees; therefore, leading to a more efficient and productive work environment.

One last thing to remember about measuring human personality is that motivations and behavior are very dynamic. This means that they have the potential to fluctuate; especially under certain situations. And that’s where many personality tests may fall short. Hence, to increase their reliability — thus, the chances for accurate results —  test-takers need to be retested, at a time that the hiring manager sees fit.