Which Personality Test Should You Use (and When to Avoid Them All)

Personality tests can be helpful, but only if used correctly. Here's what you need to know:

• Best for teamwork and communication: MBTI and DiSC help improve collaboration and understanding among team members.
• Best for hiring and performance: The Big Five (OCEAN) is reliable for predicting job performance and fitting roles.
• Best for personal growth: The Enneagram digs into motivations and self-awareness.
• Specialised tools: Clinical tests like MMPI and 16PF are for high-stakes roles but need expert administration.

When to Avoid Personality Tests:

• Don’t use them as the sole basis for hiring or promotion.
• Avoid tools with poor reliability or scientific backing.
• Skip them if they oversimplify or stereotype behaviour.

Quick Comparison Table:

Key takeaway: Choose the right test for your needs, combine it with other methods, and avoid relying on them for critical decisions like hiring.

1. Myers-Briggs Type Indicator (MBTI)

Theoretical Basis

The MBTI was developed by Isabel Myers and her mother Katherine Briggs, drawing inspiration from Carl Jung's theory of psychological types. At its core, the MBTI suggests that individuals have distinct preferences in how they perceive and interpret their experiences. These preferences influence their interests, motivations, and values.

"The MBTI is designed to implement a theory; therefore, the theory must be understood to understand the MBTI".

This framework organises people into 16 personality types, determined by four key dichotomies. Each type is represented by a four-letter code, such as INTJ or ESFP, based on the following preferences:

This theoretical foundation supports its practical applications, particularly in team development and leadership communication.

Ideal Use Case

The MBTI is widely used to improve teamwork and leadership effectiveness. For instance, research shows that 87% of Extraverts report leadership potential, compared to 56% of Introverts. As one source summarises:

"MBTI is a powerful tool to determine your leadership style and how it interacts with the personalities of those you lead".

In workplace teams, a mix of personality types can enhance collaboration by bridging communication gaps and fostering diverse approaches.

Strengths

The MBTI promotes self-awareness, helping individuals understand how they process information, manage stress, and prefer to learn. With approximately two million adults in the US taking the MBTI annually, its widespread usage ensures many are already familiar with its concepts. This familiarity makes it a popular choice for personal and professional development.

Weaknesses

Despite its popularity, the MBTI has faced substantial criticism from the scientific community. It has been described as pseudoscientific, with limited support from psychologists and researchers. One issue is its moderate test-retest reliability, meaning results can vary if the test is taken multiple times.

The binary nature of the MBTI's categories is another point of contention. By forcing individuals into one of two options for each trait, it oversimplifies personality, which exists on a spectrum. Critics also argue that its terminology can be vague enough to apply to almost any behaviour [14, 17]. Furthermore, in workplace settings, the MBTI has limited ability to predict job performance, with its dimensions overlapping significantly with the more scientifically robust Big Five personality traits.

UK-Specific Adaptations

The MBTI Step I was standardised for the UK in 1998, using a local sample and removing older gender-specific scoring methods. In line with the Equality Act 2010, UK employers must ensure that assessments, including the MBTI, accommodate candidates with disabilities.

"People with disabilities have a big contribution to make to British industry and commerce, but they are under-represented in the workplace. Psychometric tests and questionnaires are one of the most objective and fair methods of selection (and personal development), but some see them as a barrier to the employment of people with disabilities" - The Myers-Briggs Company Limited.

In June 2023, updated Accessibility Guidelines were introduced to align with UK law. These updates ensure assessments are accessible to individuals with a range of needs, including visual, dyslexic, neurodiverse, hearing, motor, speech, and learning disabilities. When using the MBTI in UK workplaces, it’s essential to ensure that the skills being evaluated are relevant to the role and that candidates are adequately prepared, with any required accommodations in place.

2. Enneagram System

Theoretical Basis

The Enneagram is a framework designed to explore human personality, categorising it into nine interconnected types, often referred to as 'enneatypes'. Its origins trace back to ancient teachings, later refined through the work of Oscar Ichazo, Claudio Naranjo, and the influence of George Gurdjieff's Fourth Way tradition.

These nine types are arranged in a 3x3 model, reflecting three Centres of Intelligence: Belly, Heart, and Head. At its core, the Enneagram seeks to uncover the motivations behind behaviour, focusing on fundamental fears and desires. As one expert puts it:

"Since the Enneagram system looks at basic fears and desires as key motivators for behaviour, and since these fears and desires are often subconscious or even unconscious, the process of discovering one's type using the Enneagram is more a quest than a report".

This emphasis on why people behave in certain ways sets the Enneagram apart from tools like the MBTI, which focuses more on cognitive preferences and what people do. These foundational ideas make the Enneagram a powerful tool for personal growth and practical applications in team and organisational settings.

Ideal Use Case

The Enneagram's strength lies in its ability to deepen self-awareness and improve interpersonal dynamics. It is particularly effective in areas like coaching, mentoring, leadership development, and conflict resolution. Within organisations, it can enhance team collaboration, reduce workplace tension, and foster better communication.

For leaders, the Enneagram offers insights into their personal motivations and blind spots, enabling more effective decision-making and team management. For example, a 2023 survey of therapists revealed that 78% found the Enneagram to be a beneficial complementary tool in improving treatment outcomes.

The nine types provide a framework for understanding diverse perspectives and behaviours:

Strengths

The Enneagram's ability to delve into the core fears and desires driving human behaviour is one of its standout qualities. Rather than merely categorising surface-level traits, it provides a deeper understanding of what motivates individuals.

Michael Norton, Co-director and teacher at The Enneagram Group, highlights its value for leaders:

"As a leader, we choose to put our attention and focus on certain areas of our work, and to ignore or override information from others. The Enneagram helps not only to recognise our strengths as a leader, but also how our worldview might be limiting our success".

The system also acknowledges that personality is not static. It views growth as a process of integration, with individuals progressing through nine levels within their type. For teams, recognising the strengths and challenges of each type can boost morale, enhance communication, and even reduce burnout. Additionally, it fosters empathy by showing that every type brings unique strengths and limitations to the table.

Weaknesses

While the Enneagram offers rich insights, its complexity can sometimes be a drawback. Rigidly applying its types can lead to stereotyping, which may stifle personal growth. Organisations risk misusing the system when they overemphasise type differences or attempt to use it as a hiring criterion.

Certain types may also face specific challenges in professional settings. For instance, Type Five leaders often struggle with maintaining emotional connections, accepting feedback that questions their expertise, and balancing their need for personal space with workplace demands.

Finally, the depth of the Enneagram, while valuable for personal and team development, can make it less practical for quick or straightforward workplace applications, where simpler tools might be more effective.

3. Big Five Inventory (OCEAN Model)

Theoretical Basis

The Big Five personality traits, also known as the OCEAN model, are widely recognised as one of psychology's most reliable frameworks for understanding personality. Unlike models based purely on theory, the Big Five emerged from analysing common personality descriptors, which consistently group into five dimensions: Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism.

The model's relevance extends beyond humans, with studies identifying similar traits in animals. Psychologist David Buss has suggested that these traits reflect essential qualities that helped early humans manage complex social interactions. By focusing on a continuum rather than fixed categories, the model provides a nuanced perspective on individual differences. This flexibility makes it particularly valuable in workplace and organisational contexts.

Ideal Use Case

The Big Five is especially effective in organisational environments where precision and predictive accuracy matter. Research indicates that 22% of companies incorporate these assessments into their hiring processes. The model is often used to predict job performance, improve team dynamics, and enhance communication. By understanding individual personality profiles, organisations can identify strengths and address potential areas of conflict, ultimately boosting productivity.

It also plays a significant role in leadership development. Leaders who understand personality differences are better equipped to manage teams effectively and foster a positive working environment.

Strengths

The Big Five model is backed by extensive scientific research. Twin studies, for instance, suggest heritability estimates ranging from 42% for agreeableness to 57% for openness. Its universal relevance is supported by cross-cultural studies spanning over 50 cultures, demonstrating the model's broad applicability. Additionally, the model's focus on a continuum - rather than rigid categories - allows for a more detailed and accurate understanding of personality.

Recent developments, such as the shorter 18-item version of the Big Five Inventory, have made the model even more practical for organisations. This streamlined version maintains strong correlations with the full-scale assessment (e.g., 0.86 for conscientiousness and 0.95 for openness), offering a time-efficient yet reliable alternative.

Weaknesses

Despite its strengths, the Big Five has faced criticism for oversimplifying the complexities of personality. Reducing human behaviour to five broad traits can sometimes miss the finer details that make individuals unique. Additionally, while the model describes personality traits effectively, it does not explain why these traits exist or how they might evolve over time.

Another challenge lies in its reliance on self-report questionnaires, which are vulnerable to biases like social desirability or inaccurate self-perception. The model's emphasis on fixed traits could also discourage personal growth. Moreover, it does not account for certain traits - such as honesty or humility - that some consider crucial. For these reasons, the Big Five is best used alongside other tools to provide a more comprehensive understanding of individuals and teams.

4. DiSC Assessment

Theoretical Basis

The DiSC Assessment has its roots in the work of psychologist William Moulton Marston, who introduced the theory in his 1928 book, Emotions of Normal People. The model revolves around four key personality traits: Dominance (D), Influence (I), Steadiness (S), and Conscientiousness (C). What sets DiSC apart is its focus on observable behaviours rather than internal thought processes.

Participants create their behavioural profiles by selecting adjectives that best describe them. This makes DiSC particularly workplace-oriented, offering practical insights for professional settings, unlike broader personality tests aimed at general self-awareness. Over the last 40 years, Wiley, the publisher of DiSC assessments, has continuously refined the model, ensuring it remains relevant and effective in modern organisational contexts.

Ideal Use Case

DiSC is especially effective in improving workplace communication and teamwork. By providing a shared framework for understanding behaviour, it helps teams communicate more clearly and manage conflicts without personalising them. For instance, teams using DiSC reported a 20% improvement in project delivery times and enhanced role allocation. Organisations also noted a 22% increase in employee retention, highlighting the tool's tangible benefits.

Managers find DiSC particularly useful for understanding their team's motivational drivers and communication styles. Armed with these insights, leaders can design personalised training programmes, form balanced teams, and make better decisions by considering diverse viewpoints. The tool even supports day-to-day workplace decisions, such as choosing between in-person meetings or online messages and planning office layouts to suit different working styles.

Strengths

DiSC’s straightforward approach and immediate applicability make it a practical choice for leaders looking for actionable insights. Unlike more complex tools like MBTI, DiSC is designed to be user-friendly for both participants and facilitators. Its reliability is backed by research, with studies showing a 90% validity rate, and it’s trusted by nearly three-quarters of Fortune 500 companies.

"The Everything DiSC® model provides a common language people can use to better understand themselves and those they interact with - and then use this knowledge to reduce conflict and improve working relationships."

The model’s focus on observable traits makes it ideal for creating tailored team exercises, improving conflict resolution, and enhancing interpersonal skills. Unlike some tools that offer generic feedback, DiSC provides actionable guidance that can be directly applied in the workplace. With over one million people using DiSC assessments annually, its practical value and ease of implementation speak for themselves.

Weaknesses

While DiSC offers many benefits, it’s not without its drawbacks. One common criticism is that it can feel overly simplistic, reducing the complexity of human behaviour into just four categories. Additionally, variations in test versions and personal biases can sometimes affect the consistency of results.

Another limitation is that DiSC focuses on providing insights but doesn’t include built-in tools for fostering behavioural change. Organisations often need to invest in additional training programmes to translate the assessment’s findings into actionable improvements. Some reports lean heavily on delivering information rather than offering developmental guidance, which can limit their practical use. Lastly, because DiSC is centred on workplace behaviour, it’s less effective in emotionally charged settings, such as counselling, where deeper psychological understanding is required. For best results, DiSC should be used alongside other evaluation methods to provide a more comprehensive view.

WHICH PERSONALITY TEST IS BEST FOR YOU? | a comparison of different personality theories

5. Clinical Instruments (MMPI/16PF)

Clinical tools like the Minnesota Multiphasic Personality Inventory (MMPI) and the 16 Personality Factor Questionnaire (16PF) are designed for deep psychological analysis, setting them apart from workplace-focused assessments.

Theoretical Basis

These instruments rely on distinct principles. The MMPI adopts an empirical method, selecting test items that effectively distinguish between individuals with and without specific psychological conditions. This approach prioritises practical item selection over adherence to a particular personality theory.

On the other hand, the 16PF, developed by Raymond Cattell, is rooted in trait theory. Using factor analysis, Cattell identified 16 core personality traits, aiming to map out normal personality in a research-driven manner. As Schuerger noted:

"Cattell's goal in creating the 16PF Questionnaire was to provide a thorough, research-based map of normal personality." – Schuerger

The 16PF measures personality traits on a spectrum, offering nuanced profiles rather than rigid categories. Completing the MMPI-2 requires 567 items and takes one to two hours, while the 16PF is shorter, taking 30 to 50 minutes.

Ideal Use Case

These assessments are tailored for specialised scenarios beyond typical workplace applications. Both the MMPI-2 and 16PF are used in pre-employment screenings, promotion evaluations, performance reviews, disability assessments, and return-to-work evaluations. However, their use must align with strict legal and ethical guidelines.

The MMPI-2, classified as a medical test under disability laws, can only be administered after a conditional job offer. For example, California mandates the use of the 16PF for selecting state police officers, highlighting its importance in high-stakes roles. The 16PF is particularly effective in "screen out" strategies to identify potential psychological risks.

In medical contexts, the MMPI-2 is invaluable in rehabilitation programmes and substance abuse treatment, focusing on conditions like anxiety, depression, and psychotic disorders. Unlike general personality tests, these tools require administration by professionals with advanced training in psychological testing, and their results should never be the sole basis for employment decisions.

Strengths

Both the MMPI-2 and 16PF are backed by extensive research. The MMPI-2 is the most extensively studied clinical personality tool, while the 16PF has been featured in over 4,000 research publications.

Each instrument includes validity scales to ensure reliable results. The MMPI-2 detects inconsistent responses and over- or under-reporting of symptoms. Similarly, the 16PF evaluates factors like Impression Management, Acquiescence, and Infrequency. By measuring traits along a continuum, the 16PF delivers detailed insights into personality, aiding complex decisions about behaviour and psychological health.

Weaknesses

Despite their strengths, these tools come with challenges. Both require expert interpretation and are subject to legal restrictions, limiting their use in routine employment scenarios. The MMPI-2’s length is another drawback, often making it impractical for organisational settings.

Since the MMPI is designed to identify psychological disorders, it can sometimes pathologise normal behaviours, making it less suitable for general team-building or leadership evaluations.

UK-Specific Adaptations

The 16PF has been re-standardised for the UK, ensuring its suitability within British contexts. Studies comparing MMPI-2 profiles between UK and US populations reveal consistent findings, with notable differences emerging only on Scale 5 (Masculinity/Femininity).

The British Psychological Society (BPS) offers detailed guidelines for test use in the UK, covering validity, reliability, and fairness. The 16PF is available in over 30 languages and dialects, while the MMPI-2 is used in more than 40 countries, with 32 different versions. These adaptations are essential to maintain fairness and effectiveness in professional settings across the UK.

Quick Comparison: Strengths and Weaknesses

When selecting a personality assessment, it’s essential to weigh its strengths and weaknesses carefully. With 88% of Fortune 500 companies relying on personality tests, UK organisations must ensure their chosen tools align with legal standards, workplace norms, and practical needs.

Different assessments offer distinct advantages and drawbacks. The table below summarises key points to help guide your decision-making:

This table provides a snapshot of each tool’s practical applications and limitations, helping organisations make informed choices.

The Importance of Implementation and Context

The success of these assessments depends heavily on how they’re applied. Studies show companies using psychometric tools effectively can see a 25% boost in productivity. However, cultural nuances matter. Research highlights that standardised test scores often vary across cultural contexts, so careful adaptation is necessary to ensure fairness and compliance with UK legal standards.

The British Psychological Society defines psychological testing as a means to infer a person’s abilities, emphasising the need for rigorous selection. While intelligence tests measure maximum performance, personality assessments focus on typical behaviour. Combining both approaches often delivers the most well-rounded insights.

Adapting Tools for UK Needs

It’s crucial to remember that most personality tests are rooted in specific cultural frameworks. For instance, tools designed for other regions may require adjustments to fit UK workplace norms, including attitudes towards hierarchy, communication, and interpersonal dynamics. This ensures the assessments remain fair, effective, and legally sound.

Ultimately, the key to successful implementation lies in matching the test’s strengths to your organisation’s specific needs, while being mindful of its limitations. The next section will delve into potential pitfalls and provide guidance on when and how to use each tool effectively.

Red Flags: Spotting Fake Science

The personality testing market is teeming with tools that promise deep insights but often deliver little more than surface-level results. With as many as 63% of job applicants admitting to faking their answers on personality tests, it’s more important than ever for UK organisations to identify unreliable tools.

Warning Signs of Pseudoscientific Tests

When evaluating personality assessments, watch out for signs of pseudoscience. One major red flag is bold claims that oversimplify personality. Scientific research supports the idea that personality exists on a spectrum, not in rigid, predefined categories. Simine Vazire, a personality researcher from the University of California, Davis, cautions:

"You should be skeptical. Until we test them scientifically we can't tell the difference between that and pseudoscience like astrology."

Tests that classify people into fixed "types" often function more like online quizzes claiming to reveal which fictional character you resemble. For instance, while 89 of the Fortune 100 companies use some form of personality testing, many of these tools lack solid scientific validation.

The Reliability Problem

Inconsistency in test results is another clear warning sign. If a personality test produces varying outcomes for the same person, it may be measuring fleeting moods rather than stable traits.

Randy Stein, a psychologist at California Polytechnic State University, Pomona, highlights the commercial bias behind some tests:

"What those tests will tell people is true or false is determined by what people are willing to pay for. Their process as a company is to tell people whatever will sell the product."

Abstract and Confusing Processes

Legitimate personality assessments should be straightforward and based on observable behaviours. Simine Vazire points out:

"If the process appears convoluted or drifts into abstract areas, that's a red flag. Personality, she says, is just not that mysterious."

Tests that rely on abstract concepts or overly complex interpretations often lack empirical grounding, leading to oversimplified or misleading portrayals of human behaviour.

The Oversimplification Trap

Another issue with unreliable tests is their tendency to focus on a narrow set of traits while ignoring others. Research indicates that such tests don’t provide a balanced view of an individual’s personality. Instead, they create a distorted and incomplete picture. This becomes especially problematic when organisations use these tests to make critical decisions, such as hiring or team placements.

Lack of Peer Review and Scientific Support

Credible personality assessments are backed by rigorous scientific research, including independent peer reviews and validation studies. When evaluating a test, look for:

• Research published in peer-reviewed journals
• Validation studies conducted across diverse groups
• Data on statistical reliability
• Endorsements from respected psychological organisations

Without this foundation, a test’s credibility should be questioned.

Ignoring Context

Unreliable tests often fail to account for situational factors that influence behaviour. They treat personality as static and unchanging, ignoring how people adapt to different environments, relationships, and circumstances. For UK organisations, this lack of contextual understanding makes such tools unsuitable for decision-making.

Before adopting any personality test, organisations should demand clear evidence of its validity. Ask for peer-reviewed studies, reliability data, and other supporting research. If a provider cannot supply this information, it’s a strong indication to look elsewhere. Even the most established tests have limitations, but the key is transparency about these boundaries rather than overpromising accuracy or predictive power.

When to Use Each Test (and When to Skip Them)

Understanding the strengths and limitations of personality tests helps determine when they're most useful and when they might lead to missteps. Choosing the right test can enhance team productivity by 12.5% and lower turnover by 25%.

For Team Building and Collaboration

Tools like the MBTI help teams grasp communication preferences, though it's worth noting that results can shift within a month. DiSC is particularly helpful for fostering better interpersonal relationships and creating a more harmonious work environment. Diverse teams, when guided by these insights, often perform 35% better in meeting deadlines and achieving goals.

The Big Five is another strong option, offering a clear picture of how individual traits shape team dynamics. It’s especially useful for assigning roles and reducing conflicts. Teams with a balanced mix of personality traits outperform more uniform groups by 23%. However, the real impact of these tests often depends on tailoring their use to specific team and organisational needs.

For Individual Development

For personal growth, focus on tests with a Cronbach's Alpha of 0.7 or higher, as these offer reliable insights. Combine test results with self-reflection to identify both strengths and areas for improvement in your career. For instance, the NEO PI-R maintains a Cronbach's Alpha above 0.8 across all five personality domains, demonstrating strong consistency.

These tools can help uncover your skills and interests, point towards promising career paths, and highlight potential challenges in the workplace. Pairing the results with self-reflection allows you to create practical reminders of your strengths and areas to watch for in specific situations.

For Organisational Decisions

Personality assessments can also inform broader organisational strategies. Regular testing has been shown to improve employee engagement by 15% and enhance adaptability within companies. However, caution is needed - research from the Journal of Applied Psychology reveals that over 30% of hiring managers misinterpret test results, leading to poor hiring decisions.

"The personality test is something that might flag a candidate who might otherwise thrive in a position that they're hired to fill." - Julie Kae, Vice President of Sustainability and Diversity, Equity and Inclusion at Qlik and Executive Director of Qlik.org

When to Avoid Testing Altogether

There are situations where personality tests should be skipped entirely. Using them to exclude candidates from employment or promotion is unethical. Similarly, hiring people who mirror the existing workforce can lead to dangerous uniformity and stifle innovation.

Tests should never be the sole criterion in high-stakes decisions. For example, a recruitment firm once rejected candidates based on low emotional intelligence scores, only to find these same individuals excelled in teamwork and leadership during a hackathon. In another case, a Fortune 500 company discovered that personality test outcomes varied significantly between stressful and relaxed environments, leading to promotions for individuals who struggled under pressure.

Making Tests Work Effectively

To maximise the value of personality assessments, focus on tools with proven predictive validity for job-relevant skills. Be transparent with candidates about why the test is being used and how the results will inform decisions. A well-rounded approach - combining personality tests with situational judgement exercises and peer reviews - often yields the best insights.

Keep in mind that people are often poor judges of their own personalities. Avoid making sweeping assumptions based on group traits; instead, focus on evaluating individuals.

Ultimately, personality tests should be one piece of a larger puzzle, offering insights to complement - not replace - other evaluation methods. They’re a tool for understanding, not a definitive guide to human behaviour.

FAQs

What’s the difference between the MBTI and Big Five personality tests, and how does it affect their workplace use?

The Myers-Briggs Type Indicator (MBTI) and the Big Five personality traits take very different approaches to understanding personality, especially in workplace contexts. The MBTI places individuals into one of 16 personality types, focusing on preferences like Introversion vs. Extraversion. Its simplicity and appeal make it a favourite for team-building exercises, but it has limited scientific support and doesn’t reliably predict workplace performance.

In contrast, the Big Five evaluates personality across five dimensions - Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism - on a spectrum. This method provides a more detailed and research-backed view of personality, making it a stronger tool for analysing behaviour and forecasting job performance. While the MBTI can be useful for encouraging self-reflection or informal team conversations, the Big Five stands out as a more credible and adaptable option for workplace applications.

Why should personality tests be combined with other methods when hiring or promoting staff?

Combining personality tests with other evaluation methods is a smart way to ensure fairer and more accurate hiring or promotion decisions. While these tests can shed light on a candidate's behavioural tendencies and how they might gel with a team, they aren't reliable enough on their own to predict job performance. They can also overlook key skills or competencies that are better revealed through structured interviews or hands-on skills assessments.

By blending different assessment tools, organisations can minimise bias and gain a more rounded view of each candidate. This strategy not only supports better decision-making but also helps match individuals' strengths to the specific demands of the role.

How can organisations use personality tests ethically and effectively in different cultural settings?

To apply personality tests responsibly and fairly across diverse settings, organisations must emphasise cultural awareness and inclusivity. It’s vital to select assessments that have been rigorously validated for use with different cultural groups. This helps reduce bias and ensures the results genuinely reflect individuals’ characteristics. Moreover, the language in these tests should be straightforward, culturally neutral, and easy to understand, avoiding any risk of misinterpretation.

Equally important is training those administering the tests to identify and manage potential biases. This ensures that results are applied fairly in decisions such as recruitment or team-building initiatives. Organisations should also make it a priority to review and refine these tools regularly, taking into account cultural shifts and feedback from employees with varied backgrounds. By doing so, they can maintain a testing process that is both fair and relevant, fostering a more inclusive environment.

Related posts

• Personality Tests: Insight or Illusion?
• Myers-Briggs: The World’s Favourite Personality Test - But Does It Hold Up?
• The Big Five: The Gold Standard of Personality Science?
• DiSC: A Simple Personality Model That Teams Love - But Is It Too Simple?