Big Five vs MBTI: Understanding Personality Types for HR in the UK and US

You need to assess candidates. Two popular tests dominate the market. One is a party trick. The other predicts performance. Which one are you using?

Why Personality Tests Matter in Hiring

Hiring the wrong person costs time and money. You need more than a resume. Soft skills, collaboration, emotional stability – these predict performance. But how do you measure them?

Personality tests promise answers. The two most common are the Myers-Briggs Type Indicator (MBTI) and the Big Five model. Both claim to reveal who a candidate really is. Yet only one has the scientific backing to support hiring decisions.

Here is the uncomfortable truth: most HR teams still use tools that are no better than horoscopes. They label people as "INTJ" or "ENFP" and assume they know how that person will behave at work. They don't.

The MBTI: Popular but Flawed

The MBTI sorts people into 16 types based on four dichotomies: Introversion/Extraversion, Sensing/Intuition, Thinking/Feeling, Judging/Perceiving. It sounds neat. It is not.

Studies show that 50 % of people get a different type when they retake the test after only five weeks. That is not a personality test. That is a mood ring. A reliable test should give the same result over months or years.

The MBTI was developed by a mother-daughter team with no formal training in psychometrics. It was never validated against job performance. And yet it remains the most widely used personality assessment in corporate training and coaching.

"Less than 1 % of academic studies on personality use the MBTI. The scientific community has moved on." – Source: Test-personnalite.app, 2023

Why Do Companies Still Use It?

Three reasons. First, it is easy to remember. "I'm an INTJ" sounds like a badge. Second, it feels positive. Every type has strengths. Nobody is "bad". That sells well in training. Third, it is cheap and quick. But cheap tools produce cheap results.

• Problem MBTI forces people into binary categories. Real personalities exist on a spectrum.
• Problem It does not measure emotional stability or neuroticism – key predictors of job success.
• Problem It has no predictive validity for hiring outcomes.

The Big Five: The Scientific Gold Standard

The Big Five (also called OCEAN) measures five continuous dimensions: Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism (or Emotional Stability). It is the result of decades of peer-reviewed research.

Test-retest reliability for Big Five scales is 0.80 to 0.90 over months or years. That means you get the same result almost every time. That is what you need for hiring decisions.

The Big Five predicts job performance better than any other personality model. A meta-analysis of over 200 studies found that Conscientiousness alone correlates with performance across nearly all occupations. Emotional Stability predicts teamwork. Extraversion predicts sales success.

What the Research Says

In a 2018 study from CLiC-it, researchers compared AI models trained to predict personality from Facebook data using MBTI labels versus Big Five labels. The Big Five models were more informative, but MBTI labels sometimes gave higher classification accuracy – because they are simpler. That simplicity is deceptive. You lose nuance.

Another source, PerformanSe, notes that Big Five coefficients of internal reliability are consistently above 0.80. They conclude that for structured professional contexts, the Big Five is "objectively more suitable" than MBTI.

Key Differences Between MBTI and Big Five

Ask yourself: are you using a test that is scientifically validated? If your tool is based on MBTI, you are flying blind. The data does not support it.

What This Means for Your Recruitment Process

You have a choice. You can keep using a test that 50 % of people fail to repeat within a month. Or you can switch to a model that actually predicts who will succeed in your team.

Here is a simple checklist to audit your current personality assessment:

1. Check the test-retest reliability. Is it above 0.80?
2. Ask if the test has been validated against job performance metrics.
3. Ensure the test measures continuous traits, not binary categories.
4. Verify that the test includes Emotional Stability (Neuroticism) – missing in MBTI.
5. Use a tool that provides actionable reports for hiring managers, not just a four-letter label.

One more thing: the Big Five is not just for selection. It helps with team building, coaching, and leadership development. It gives you a shared language without boxing people into stereotypes.

Why Sigmund Tests Use the Big Five

At Sigmund, we built our assessments on the Big Five model. Why? Because we care about results, not labels. Our personality test delivers reliable scores on all five dimensions, backed by normative data from thousands of professionals.

We also offer a full catalogue of validated assessments for different HR needs – from hiring to succession planning. Every test is designed to give you clear, actionable insights.

Stop guessing. Start measuring. Explore our HR assessments

Or if you prefer, read more about the science behind personality testing on our HR news page.

Move Beyond the MBTI Debate: Make Data-Driven Hiring Decisions

Why the Big Five Outperforms MBTI in Hiring

A 2023 literature review of 14 empirical studies confirmed the Big Five’s broader and more rigorous application in formal contexts (education, research, corporate). Correlations between MBTI scales and Big Five factors exceed 0.50. For example, Extraversion/Introversion maps directly to Extraversion. Sensing/Intuition maps to Openness. MBTI offers no unique structural dimension.

The Big Five measures observable, conscious traits on a continuum. No forced choices. No dichotomies. This means you get granular data, not a static label. And you can compare candidates objectively.

Your Actionable Checklist for Better Assessments

Stop the debate. Start applying what the science says. Here is a concrete checklist for HR professionals:

• 1. Replace any MBTI-based screening with a Big Five assessment. Use the same budget—get better data.
• 2. Focus on the two strongest job predictors: Conscientiousness and Emotional Stability. Research shows these correlate with performance in most roles.
• 3. Interpret scores as continuous percentiles (e.g., candidate scores 78th percentile on Agreeableness) — not as types. This lets you compare candidates directly.
• 4. Combine personality data with structured interviews and skills tests. Personality is one piece, not the whole puzzle.
• 5. Validate your chosen test internally: track performance ratings against assessment scores after 6 months. Adjust thresholds.

“The MBTI is useful for self-reflection and informal exploration. But when you need to predict who will succeed in a role, the Big Five is the gold standard. It’s not about which test is more popular—it’s about which one works.”

One Model, Multiple Applications

The Big Five framework adapts to every HR need. Use it for recruitment, team composition, leadership development, and coaching. Each trait gives you actionable insight:

• High Conscientiousness? Great for roles requiring planning and detail orientation.
• Low Neuroticism (High Emotional Stability)? Handles pressure well. Ideal for crisis management.
• High Openness? Drives innovation. Perfect for R&D and creative teams.
• High Extraversion? Thrives in sales, customer-facing positions.
• High Agreeableness? Builds cooperation. Key for team-based support roles.

You can benchmark your current team against these dimensions. Then define ideal trait ranges for each position. This transforms hiring from a guess into a science.

Test Your Own Candidates, Not Your Beliefs

SIGMUND’s personality test uses the Big Five model with no shortcuts. Every candidate receives a transparent, percentile-based report. No vague descriptions. No “types.” Just clear data you can act on.

Take the first step. Explore our full test catalogue to see how each assessment maps to real job requirements. Or go deeper into our standalone personality test to understand the traits that matter most for your roles.