The Coach's Guide to Personality Assessments: A Data-Driven Comparison
The Coach's Guide to Personality Assessments: A Data-Driven Comparison
In the coaching world, personality assessments have become as ubiquitous as coffee meetings and breakthrough moments. But with so many options available—from the workplace favorite DISC to the spiritually-inclined Enneagram—how do you know which tools deserve a place in your coaching toolkit?
By Alexander Mills
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mbtimyers-briggspsychology
In the coaching world, personality assessments have become as ubiquitous as coffee meetings and breakthrough moments. But with so many options available—from the workplace favorite DISC to the spiritually-inclined Enneagram—how do you know which tools deserve a place in your coaching toolkit?
The Stakes Are Higher Than You Think
Recent research analyzing over 6,000 participants found that while Big Five personality assessments predict life outcomes with impressive accuracy, MBTI-style tests perform significantly worse, achieving prediction rates that would be 38% better if they didn't force people into binary categories. For coaches making recommendations that impact careers, relationships, and life decisions, this isn't just academic—it's professional responsibility.
The Personality Assessment Landscape: By the Numbers
The coaching industry's relationship with personality assessments is extensive and growing:
MBTI dominance: Over 2.5 million people take the MBTI assessment annually, with organizations reporting 35% increases in workplace harmony post-evaluation
Big Five adoption: 467 Fortune 500 companies were using personality assessments in 2015, with increasing preference for Big Five-based tools due to superior predictive validity
StrengthsFinder reach: More than 26 million people had taken the CliftonStrengths assessment as of 2022
Hogan penetration: Over two-thirds of Fortune 500 companies are Hogan Certified
Assessment Deep Dive: What the Science Says
Myers-Briggs Type Indicator (MBTI): The Popular Problematic
The Reality Check
When comparing MBTI-style tests to Big Five assessments in predicting 37 life outcomes, researchers found that adding MBTI results to Big Five ones didn't improve predictions at all. More concerning, studies show about 50% of participants receive different types when retesting after just 5 weeks.
Reliability Issues:
Test-retest reliability: 50-75% consistency (compared to 70%+ gold standard)
Dichotomous scoring creates artificial categories where someone scoring 51% introversion gets the same "I" label as someone scoring 95%
Coach Consideration: Despite reliability issues, 88% of MBTI users report greater understanding of workplace dynamics. The framework excels as a conversation starter and common language tool, particularly valuable for team-building exercises.
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The Big Five (OCEAN): The Scientific Standard
The Gold Standard
Meta-analyses consistently show Big Five traits demonstrate stronger associations with important life outcomes, including relationship satisfaction, leadership effectiveness, and mental health. The Big Five achieved meaningful prediction accuracy while MBTI-style tests often failed.
Scientific Backing:
Reliability: Internal consistency typically .80-.90
Validity: Consistently predicts job performance, with Conscientiousness and Extraversion as strongest predictors
Universality: Replicated across cultures, languages, instruments, and theoretical frameworks
Practical Advantages:
Continuous scoring (more nuanced than types)
Culturally robust
Extensive research base (thousands of studies)
DISC: The Workplace Workhorse
Reliability Profile
DISC assessments show good-to-excellent reliability with median coefficient alpha of .87 and test-retest reliability of .86. Everything DiSC reports 97% satisfaction rating among organizations and 90% accuracy rating from learners worldwide.
The Mixed Verdict:
Strengths: Reliability scores fall within "Very Good to Excellent" range (.83-.93 for each style)
Limitations: Studies show DISC assessments have demonstrated no ability to predict job performance, with validity concerns
Usage: Used by almost three-fourths of Fortune 500 companies and all branches of U.S. military
Coach Application: DISC excels for behavioral awareness and communication style adaptation. About 80-90% validity for behavioral prediction makes it powerful for team dynamics, though limited for performance prediction.
Enneagram: The Spiritual Seeker's Tool
Scientific Standing
A comprehensive review of 104 independent samples found mixed evidence of reliability and validity, with factor analysis typically finding fewer than nine factors. 87% of individuals were able to accurately predict their Enneagram type before taking the test by reading descriptions.
The Research Reality:
Limited peer-reviewed research
Experts describe it as "pseudoscientific at best" due to lack of empirical derivation
Rated by 25% of doctoral-level psychologists as discredited for personality assessment
Coaching Value: Despite scientific limitations, several studies found the Enneagram helpful for personal/spiritual growth. Most valuable for motivation exploration and self-reflection rather than predictive assessment.
CliftonStrengths (StrengthsFinder): The Talent Spotter
Research Foundation
Based on 30+ years of Gallup research with excellent test-retest results and high degree of stability over several years. Studies of over 57,000 people show CliftonStrengths results remain consistent over time with little change across years and demographic groups.
Coaching Applications:
Career Development: Strong for identifying natural talent patterns
Team Building: Four domains (Executing, Influencing, Relationship Building, Strategic Thinking) provide team composition insights
Leadership Development: Used by 467 Fortune 500 companies for leadership assessment
Limitations: Critics argue exclusive focus on strengths can create blind spots and prevent addressing crucial weaknesses.
Hogan Assessment Suite: The Executive's Choice
Triple-Focus Approach
Hogan uniquely measures "bright side" (normal personality), "dark side" (potential derailers), and "inside" (values/motivation). Hundreds of research studies validate these assessments as consistent, reliable measures that predict workplace performance.
Executive Coaching Gold Standard:
Reliability: Strong internal consistency and test-retest reliability
Validity: Hundreds of validation studies demonstrate extent to which assessments predict performance
Application: One million personality assessments processed annually with over 13 million total completions
Unique Value: The only psychometric tool specifically scrutinizing potential career derailers and behaviors under pressure, making it invaluable for executive coaching.
Predictive Accuracy Comparison
Assessment
Life Outcome Prediction
Test-Retest Reliability
Scientific Studies
Best Use Case
Big Five
High (Best performer)
.80-.90
Thousands
Individual assessment, performance prediction
Hogan Suite
High (Executive context)
.85-.90
400+
Leadership development, executive coaching
DISC
Low (Behavior only)
.86-.87
Moderate
Communication styles, team dynamics
CliftonStrengths
Moderate (Strengths focus)
.85+
Moderate
Talent development, strengths coaching
MBTI
Low (38% could improve)
.50-.75
Limited positive
Team building, conversation starter
Enneagram
Very Low
Mixed
Very Limited
Spiritual growth, motivation exploration
Coach Type Recommendations: What Should You Know?
Life Coaches
Primary Tools: Big Five + CliftonStrengths
Big Five for comprehensive personality understanding
StrengthsFinder for talent-based development
Avoid: Relying solely on MBTI or Enneagram for major life decisions
Executive Coaches
Primary Tools: Hogan Suite + Big Five
Hogan tools provide comprehensive insights into strengths, weaknesses, and potential derailers essential for leadership effectiveness
Big Five for foundational personality assessment
Consider: DISC for communication coaching
Wellness Coaches
Primary Tools: Big Five + Enneagram (carefully)
Big Five for evidence-based personality insights
Enneagram for motivation and growth conversations
Caution: Present Enneagram as exploration tool, not scientific assessment
Health Coaches
Primary Tools: Big Five + Health-specific measures
Research shows Conscientiousness from Big Five positively correlates with health-related behaviors and physical health
Focus on traits that predict health behavior adherence
Academic Research: Big Five dominant (thousands of studies vs. limited for others)
Executive Development: Hogan Suite leading, Big Five growing
Personal Development: MBTI and Enneagram popular despite scientific limitations
The Surprising Truth About Accuracy
Recent research comparing framework accuracy found that when people rated how well each assessment described them, the results were eye-opening: Jungian/MBTI-style (1.7/7), Big Five (1.6/7), and Enneagram (1.3/7). However, feeling accurate and being predictively valid are completely different things.
This explains why people often defend MBTI results even when research shows poor predictive validity—the descriptions feel personally resonant even when they don't predict real-world outcomes.
Implementation Guidelines for Coaches
Evidence-Based Practice Standards
Primary Assessment: Use Big Five or Hogan Suite as foundation
Supplementary Tools: Add DISC, StrengthsFinder, or Enneagram for specific purposes
Client Education: Explain the difference between "feeling accurate" and "scientifically valid"
Ethical Responsibility: When assessments are applied in high-stakes situations like workplaces, issues of ethics and fairness require working with evidence-based tools
Red Flags to Avoid
Using MBTI or Enneagram alone for major career decisions
Presenting any assessment as definitive rather than exploratory
Ignoring scientific validity in favor of client preference
Big Five: For comprehensive, scientifically valid personality assessment
Hogan Suite: For executive and leadership coaching contexts
Tier 2 (Reliable Tools with Limitations)
CliftonStrengths: For strengths-based development (acknowledge blind spots)
DISC: For communication and behavioral awareness (not performance prediction)
Tier 3 (Use with Caution)
MBTI: As conversation starter only, not for major decisions
Enneagram: For motivation exploration and spiritual growth discussions
Future-Proofing Your Practice
The personality assessment landscape continues evolving, with organizations increasingly seeking tools that combine Big Five traits with modern data analytics to enhance predictive validity. As a coach, staying current with scientific developments while maintaining practical utility will differentiate your practice.
The most successful coaches aren't those who use the most popular tools—they're those who use the most appropriate tools for each client's needs, grounded in scientific evidence and applied with professional wisdom.
Remember: Personality assessment is about understanding what people are like and helping them navigate their unique psychological makeup. Choose your tools accordingly.
Citations
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