Big Five vs HEXACO: Which Personality Model Is Right for Leadership Development?

If you have spent time in leadership development, you have almost certainly encountered the Big Five personality model. It is the most empirically validated personality framework in the world — the result of decades of psychometric research across cultures, occupations, and languages. It measures five broad dimensions: Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism (often reframed as Emotional Stability).

HEXACO is less widely known but, in several important respects, more useful for the specific work of leadership development at the senior level. Here is why — and when each one is the right tool.

What the Big Five measures

The Big Five (also called OCEAN) emerged from lexical analysis — the idea that the most important personality characteristics will, over time, be encoded in the vocabulary of any language. By analyzing which personality descriptors cluster together across thousands of subjects, researchers converged on five relatively stable, universal dimensions.

In leadership contexts, the Big Five predicts several things reliably: Conscientiousness is the strongest predictor of job performance across virtually every occupation studied. Extraversion correlates with leadership emergence. Openness to Experience is associated with innovation and tolerance for ambiguity. Emotional Stability predicts performance under pressure. Agreeableness is complex in leadership contexts — it supports relationship quality but can undermine the willingness to hold people accountable.

What HEXACO adds

HEXACO was developed by Kibeom Lee and Michael Ashton as a response to a consistent finding in cross-cultural personality research: the Big Five did not fully capture a personality dimension that appeared reliably across multiple languages. That sixth dimension is Honesty-Humility. It measures sincerity, fairness, greed-avoidance, and modesty. People low in Honesty-Humility tend to be manipulative, self-aggrandizing, and willing to exploit others for personal gain. People high in it tend to be principled, transparent, and genuinely unconcerned with status for its own sake.

Honesty-Humility is not the same as agreeableness. A leader can be highly agreeable — warm, cooperative, easy to work with — while being quite low in Honesty-Humility. They might be pleasant to interact with while being quietly driven by status or personal advantage in ways that compromise their integrity under pressure.

This distinction has direct implications for leadership development at the senior level, where the stakes of integrity failures are highest and where sophisticated self-presentation can mask the underlying trait quite effectively.

When to use each model

Use Big Five when:

• The development goal is performance, communication style, or team effectiveness — areas where the five-factor model has the deepest research base.
• The leader is working on a specific behavioral pattern that maps clearly to one of the five dimensions.
• The organization uses Big Five as part of its existing talent infrastructure and you are building on an established assessment.

Use HEXACO when:

• The development goal involves leadership integrity, ethical decision-making, or culture-building — areas where Honesty-Humility is particularly relevant.
• The leader is navigating a role transition requiring a more fundamental examination of values and motivations, not just behavioral tendencies.
• The leader has high interpersonal sophistication and you want a model that surfaces what lies beneath that presentation.

Why this decision matters more than most leaders realize

Assessment tools in leadership development are often treated as interchangeable. They are not. The model you use shapes what aspects of personality become visible and what aspects of development become available to work on. A leader whose most significant opportunity lies in their relationship with integrity will get a competent but incomplete picture from a Big Five-only approach — they will work on the right behaviors while leaving the underlying driver intact.