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How to Set Your Personality Tests for Success

Talent Assessment | 6 Min Read

How to Set Your Personality Tests for Success

Personality Testing Approaches: Trait-based vs. Type-based

The trait approach and the type approach are the two schools of thought concerning personality testing, and both focus on people’s characteristics. However, they differ substantially in how they use them to describe people.



The Type-based Model

The type-based approach characterizes people according to specific qualitatively distinctive categories. An individual usually fits in one or two categories that describe his/her typical behavior. A ‘type’ is purely a class of individuals sharing a collection of characteristics.

Behavior, in this approach, is not viewed as caused by one’s ‘type.’ Rather, it is an expression of the ‘type’ in which an individual is categorized. It is common to identify ‘type’ differences by describing consistent sets of associated traits. We do this in our daily observations of the ‘type.’

The popular Myers-Briggs Test (MBTI) is rooted in the type-based theory. It’s a tool designed specifically for personal use, for people on the path to self-discovery – to use their strengths to their advantage. However, using MBTI to make high-stakes decisions on hiring, for instance, has been under the scanner. Many psychometricians believe that MBTI may not be the right tool for decision-making, especially in the workplace setting. Even though the type theory is used widely, many psychologists believe personality to be much more than a binary function.

The Trait-Based Model

The trait theory views personality as a function of multiple traits wherein they are the building blocks of human personality. The trait-based model theorizes that every individual has a common set of traits. However, each trait’s degree varies across individuals. Hence, individuals merely differ in the quantum of a trait they possess. This difference in the traits’ prevalence determines the demonstration of positive or negative behaviors. We act in specific ways because of some underlying traits that activate a particular response or a level of response.

The trait-based approach considers individual differences. Therefore, it is more suited for making people decisions at the workplace. Based on the desired behaviors (i.e., competencies in an organization’s context), understanding the relevant traits’ presence helps gauge an individual’s likelihood of demonstrating them.

The Big Five theory is modeled after the trait-based approach and is most widely used to assess and predict workplace performance, trainability, job satisfaction, etc. The Big Five model has undergone several iterations, making it more accurately applicable in the workplace, owing to its high validity and reliability.


The Preference for the Trait-based Theory in the Workplace

The trait-based approach is usually preferred the most to assess personality in the workplace. It allows you to compare two individuals on the same set of parameters quantitatively.

The trait-based model tends to be distributed normally. Statistical research indicates that about 68 percent of the people tested scored in the middle range – with a decreasing percent scoring by the extremes. In contrast, type dimensions are not distributed normally in the population – why some types are more prevalent than others. Therefore, those categorized under certain types may not be deemed fit for most roles in a conventional organization.

‘Type’ is normative in the type-based approach. One does not have a ‘type’ to be or a ‘normal’ or ‘best’ score to obtain. Most type-based tools are not quantitative. Hence, it is challenging to track the development or improvement in desired behaviors or competencies over a prolonged duration, even within a particular type.

Individuals can be placed on an infinite number of places on the sliding scales of traits, using the trait theory approach. However, the type-based assessment identifies with a limited number of ‘types.’ The desired behaviors for a certain requirement may be somewhat diverse, depending on the organizations’ dynamic expectations. Hence, trait-based assessments allow focusing on the relevant traits and understanding an individual’s readiness.


Personality Testing in the Workplace


Personality tests intended for commercial use undergo rigorous quality checks. They are standardized as per the standards defined by recognized bodies, such as AERA (The American Educational Research Association), APA (The American Psychological Association), NCME (The National Council on Measurement in Education) and EFPA (European Federation of Professional Psychologists’ Associations). Other such recognized bodies include Uniform Guidelines on Employee Selection Procedures (EEOC, 1978) and SIOP (The Society for Industrial and Organizational Psychology). All of them are experts in I-O psychology.

The theory backing the personality test is perhaps more important than the test. A personality test’s validity and reliability are rooted in a scientific framework while allowing flexibility within a defined structure. The guidelines ensure that the assessments are free from any adverse impact across age, gender and ethnicity. Consequently, they can be used across diverse populations, irrespective of age, gender, education and native language.

There is no concept of a universal personality test. However, norming comes to play here. Each personality test you use is normed considering a certain heterogeneous group, with a representative sample of diverse ages, gender, education, etc. Norming is an important consideration when choosing a personality test for a specific subset of people.

You can set your personality tests for success by considering the following:

  • Define your objectives and competencies critical to the role in consideration, i.e., clarify whether you would use the tests for learning and development purposes or shortlisting and selection.
  • Ensure that the test is developed by a recognized team of subject matter experts.
  • Validity and reliability are important properties for a test to provide results that help make important talent management decisions. 1. Psychometric validity refers to an assessment’s potential to evaluate what it claims to measure. It simply means that a test’s high validity guarantees that the test items or questions are closely linked to its intended core focus., 2. Psychometric reliability is an essential component of psychometric tests. It refers to the extent to which the scores are consistent across multiple instances of testing, numerous test editions, or multiple raters grading a participant’s responses. High psychometric reliability means the scores are precise, consistent and can be recreated repeatedly.
  • Personality tests are best used as part of an assessment battery to provide a holistic view of a test-taker. They can be clubbed with aptitude tests, domain tests, situational questionnaires, etc., to make critical hiring and development decisions.
  • Personality tests can be used as a supplementary tool to gauge cultural fitment and a person’s preferences.



The Big Five model lists five broad personality factors that can be broken into narrower facet-like constructs. They form the building blocks of a personality test. When customizing a personality test to suit your organizational needs, a psychometrician needs to identify the relevant facets of the personality tool that needs to be mapped to the competencies under consideration while being mindful of the required standards.

To sum up, as SIOP posits, “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.”




Mercer | Mettl’s Personality Assessments

Mettl Personality Map


Mettl Personality Map (MPM) is a comprehensive personality test that measures personality via a unique and innovative 28 facet and a four-factor structure of personality for work-related outcomes, beyond the well-established ‘Big Five’ model of personality. The model used five broad personality traits, categories to describe people. Behavioral tendencies are broadly categorized into four factors:


Mettl Personality Map


  • Self: The ability to remain strong and positive and display positive character at work.
  • People: The ability to understand people and interact with them at work.
  • Goal: The tendency to plan, pursue and achieve one’s goal.
  • Lead: The ability to take the initiative and ownership of things around oneself.


The Rigor of the Tool:

Reliability The median reliability is 0.75 at the facet level and 0.90 at the factor level.
Validity Convergent validity estimates range from 0.3 to 0.51 and criterion validity estimates range from 0.25 to 0.51.
Scaling 6-point Likert Scale
Norming Over 3000 respondents across geographies, including Europe, North America, Australia, New Zealand, Latin America, Asia and Africa
Adverse impactIt is free from adverse impact bias. The mean group difference is mostly insignificant among ethnic, age and gender groups.
Team membersMembers of SIOP (The Society of Industrial and Organizational Psychology)
Tool developmentIn accordance with: 1. APA (American Psychological Association) standards, 2. The Equal Employment Opportunity Commission (EEOC) guidelines, 3. The Association of Test Publishers (ATP) guidelines

Mettl Personality Profiler


Mettl Personality Profiler (MPP) is modeled after the Big Five theory, which specifies that people can be described based on their standing on five broad personality traits. Mercer | Mettl’s scientists went beyond the well-established model of the broad ‘Big Five’ personality factors and developed 26 scales or narrower facet-like constructs, which form the building blocks of our assessment.

These scales span a wide domain of personality and are mapped to an organization’s or job role’s specific performance models or behavioral competencies to predict job success optimally.

The ‘Big Five’ personality traits predict important job-related outcomes, such as job performance, a person’s potential for burnout, trainability and job satisfaction.

The five factors are:

  • Extraversion (outgoing/energetic vs. solitary/reserved)
  • Openness to experience (inventive/curious vs. consistent/cautious)
  • Emotional stability (secure/confident vs. sensitive/nervous)
  • Agreeableness (friendly/compassionate vs. cold/unkind)
  • Conscientiousness (efficient/organized vs. easy-going/careless)


The Rigor of the Tool:

Reliability (Cronbach alpha) 0.63 to 0.88
Validity (Convergent)0.4 to 0.75
Norming and standardizationNormed on a sample of over 37000 respondents across geographies, including India, US, Europe, South Africa and Southeast Asia (representative sample with different age, gender, job level and occupations)
Adverse impactThe tool has also been tested for adverse impact regarding age, gender and ethnicity, for which mean group differences for the MPP are examined. The mean group difference is mostly insignificant among ethnic, age and gender groups.
Team membersPart of SIOP (The Society of Industrial and Organizational Psychology)
Tool developmentIn accordance with APA (The American Psychological Association) and EEOC (The Equal Employment Opportunity Commission)
Test design guidelinesBy ATP (The Association of Test Publishers)

Originally published April 1 2021, Updated March 5 2024

Written by

Bhuvi is a content marketer at Mercer | Mettl. She's helped various brands find their voice through insightful thought pieces and engaging content. When not scandalizing people with her stories, you’ll find her challenging gender norms, dancing to her own tune, and crusading through life, laughing.

About This Topic

Personality assessments are a method of identifying candidates whose characteristics match the role and organization’s requirements. Personality assessments help HRs make effective people decisions by placing people in positions suited to their disposition.

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