Fact vs. Fiction in Personality Testing

6 min readApr 14, 2021


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Have you ever taken a personality test that’s left you feeling misrepresented?

Personality tests that lack validity are poor indicators of workplace performance and, like the documentary ‘Persona: The Dark Truth Behind Personality Tests’ explains, should not have a place within recruitment.

Learn how to recognize fact from fiction in personality assessments as we explore how, and why measuring personality plays a key role within organizational decision making.


Establishing fact from fiction in the world of personality assessments means being able to distinguish an assessment that adds value to your organization and follows scientific principles, from one that does not.

The recently broadcast ‘Persona: The Dark Truth Behind Personality Tests’ has unfortunately blurred the boundary between effective, and ineffective personality assessments. Despite the extensive evidence suggesting otherwise, the film goes so far as to suggest that all personality assessments are ineffective, invalid, and even unethical to use for organizational decision making. In this article, we seek to clarify and provide guidance to those looking to establish fact from fiction.

Personality questionnaires offer an opportunity for organizations to efficiently identify the most aligned candidates for a position by translating their behavioral preferences into specific characteristics that can predict their future performance in the workplace.

However, for both candidates and employers to truly glean the full benefits of this process and effectively eliminate bias, the personality questionnaire must have strong psychometric properties, as well as be relevant, job-related and most importantly — valid.

A personality questionnaire that can fulfil these criteria can be safely used to predict relevant, real-life behavior.

10x Psychology have compiled a list of the top questions to ask when looking to incorporate a personality assessment for organizational decision making.

What is the value of using a Personality Assessment?

Personality assessments can identify the soft-skills and competency potential of any individual. Decades of research into the effectiveness of job-related, trait-based personality questionnaires have proven personality assessments to be consistent and effective predictors of job success[1]. However, it is important to only focus on the relevant competencies that are key for successful performance within a role — this eliminates bias and enables a fair, objective comparison between all candidates.

Therefore, it is integral that a thorough job analysis is conducted as a first step in candidate assessment. Based on the key traits identified from the job analysis, a personality assessment can be integrated as part of the selection process as a key measure of a candidate’s potential.

At 10x Psychology, we support organizations in identifying these key traits, alongside the key abilities and drivers for successful performance. Data from our range of industry leading psychometric assessments supplemented by structured, competency-based interview scores are compiled and translated onto our interactive dashboard where you can objectively, quickly, and effectively identify talent.

Do personality assessments introduce bias or measure elements of mental health?

Personality questionnaires that are scientific, trait-based and designed for the workplace are not diagnostics of mental health, nor should they ever be used for such purposes.

A comprehensive personality assessment that maps onto the Big Five factors of personality, includes scales that could be perceived as problematic such as traits of emotional stability — these may be construed as related to elements of a person’s mental health. However, a clear distinction needs to be made between how, and in what context this type of scale is used, as well as which elements of the assessments are used for decision making.

Workplace personality assessments should only feature questions that relate to behavior in the workplace, and never include questions that are not compliant with employment laws. These questions should measure individual differences on the continuum of normal personality only and not veer into the maladaptive extremes (the dark side) of personality traits.

The crux however of appropriately using a comprehensive personality assessment lies in its job-relevance, only those elements that are related to the role should be used to inform decision making. By focusing on job-relevant behaviors only, the outcomes will be fair and non-discriminatory, and eliminate, rather than introduce bias as suggested by the documentary.

“There is a dark side to personality assessments, or indeed any assessment, when they are not used responsibly or researched properly. However, there is also a bright side to personality assessments when used in an appropriate, evidence-based manner, by well-trained professionals.”
SIOP response to HBO Documentary, 2021

Why is it important to distinguish between Traits and Types?

Personality assessments fall within two broad categories: they either measure types or traits. Type questionnaires, such as the Myers Briggs Type Indicator (MBTI) described in the documentary, essentially assigns a label that classifies candidates into a single type. For example, on the extraversion scale a candidate would be classified as either introverted or extraverted — this information would then feed into the type the candidate is assigned to.

In reality, extraversion is not dichotomous — rather than being either one or the other (extroverted or introverted), each individual would fall somewhere across this extraversion continuum.

Trait questionnaires treat personality as a set of continuous characteristics, where candidates have varying levels of each trait and can be best described in terms of their unique mix of multi-faceted personal preferences. Trait-based measures are stable and have been consistently shown to predict job-relevant outcomes. By contrast, type-based measures are unstable, and often result in alternate types being ascribed across time and unsurprisingly lack evidence of predictive validity.

The documentary ‘Persona: The Dark Truth Behind Personality Tests’ focused exclusively on the use of the MBTI within hiring and selection in America — we would like to acknowledge that the use of the MBTI in recruitment is inappropriate and is in no way representative of assessments that are scientifically developed, trait-based and workplace oriented.

“We must move to a situation where the information we obtain at selection is validated, open, transparent and available to our people.”
Professor Peter Saville — Founder of 10x Psychology, Testing Times

How will the assessment affect the candidate experience?

Appropriately developed personality tests provide candidates with a comprehensive insight into who they are in a work context and are commonly viewed as relevant and fair by test-takers[2]. To empower candidates to perform at their best in the recruitment process, it is important for organizations to consider the WCAG guidelines on accessible systems[3] . Assessment platforms that comply with these have a wider reach and enhance accessibility for neurodiverse candidates, boosting inclusivity in recruitment.

An individual’s experience of your organization’s recruitment practice is a key public touchpoint. Personality assessments that are accessible, intuitive to complete, relevant and include the provision of insightful feedback are far more likely to cultivate a positive impression and to reflect well on your organization’s brand.

At 10x Psychology, our assessment platform and psychometric assessments have been designed with accessibility in mind. The questions asked within the assessments themselves are short, concise, and culturally neutral and offered in multiple languages. In addition to this, our candidate platform is mobile-friendly, color-blind optimized, with dyslexia-friendly font options and other inbuilt accessibility features.


Personality assessments that are developed for the workplace and proven to predict job relevant outcomes can be an invaluable resource for both candidates, and employers in understanding and facilitating crucial organizational decision making across talent acquisition and development.

Click here to read our official response to HBO’s Documentary.


Anderson, N., Salgado, J. F., & Hülsheger, U. R. (2010). Applicant reactions in selection: Comprehensive meta‐analysis into reaction generalization versus situational specificity. International Journal of Selection and Assessment, 18(3), 291–304.

Dudley, N. M., Orvis, K. A., Lebiecki, J. E., & Cortina, J. M. (2006). A meta-analytic investigation of conscientiousness in the prediction of job performance: Examining the intercorrelations and the incremental validity of narrow traits. Journal of Applied Psychology, 91, 40–57. doi:10.1037/0021–9010.91.1.40

Salgado, J.F., & Táuriz, G. (2014) The Five-Factor Model, forced-choice personality inventories and performance: A comprehensive meta-analysis of academic and occupational validity studies, European Journal of Work and Organizational Psychology, 23:1, 3–30. doi:10.1080/1359432X.2012.716198

Saville, P., Sik, G., Nyfield, G., Hackston, J., & MacIver, R. (1996). A demonstration of the validity of the Occupational Personality Questionnaire (OPQ) in the measurement of job competencies across time and in separate organisations. Applied Psychology: An International Review, 45, 243–262. https://doi.org/10.1111/j.1464-0597.1996.tb00767.x

WCAG 2.1: Web Content Accessibility Guidelines (WCAG) 2.1. Retrieved from W3C: https://www.w3.org/TR/WCAG21/

[1] i.e., Saville et al., 1996, Dudley et al., 2006, Salgado & Tauriz, 2014

[2] Anderson et al., 2010

[3] WCAG 2.1




Founded by Professor Peter Saville, 10x Psychology significantly improves people performance in the workplace through insight, science and technology