Both frameworks claim to measure personality. They disagree on almost everything else — what a result is, how stable it's supposed to be, and what a middling score even means.
What each one is actually built from
The Big Five wasn't proposed by one person. It's the product of decades of independent factor-analytic research converging, repeatedly, on the same five-dimension structure — a finding that kept surviving re-tests rather than being asserted once and left alone. MBTI runs the opposite direction: Katharine Briggs and Isabel Myers built it directly from Carl Jung's theory of psychological types, a fixed framework applied to people rather than a structure derived from how people's answers actually cluster. One model was discovered by repeatedly checking; the other was designed and then applied.
A continuous score vs. a forced binary
This is the mechanical difference that drives most of the practical ones. MBTI's four dichotomies (e.g., Introversion/Extraversion) split every respondent into exactly one of two boxes — there's no result that says "close to the middle." The Big Five scores each dimension on a continuous scale instead, and Bearing's own facet scoring makes the consequence of that concrete: a mid-range score isn't rounded up or down into a category, it's read as its own distinct result, specifically predicting that the trait shows up situationally — present in some contexts, absent in others — rather than consistently in either direction. MBTI has no equivalent output. Someone who's genuinely near the middle on Introversion/Extraversion still gets handed one letter, because the framework has no third option to hand them instead.
Why retaking MBTI so often changes the result
Research on MBTI's psychometric properties (Pittenger, 2005) has repeatedly found weak type-retest reliability — a meaningful share of people who retake it land in a different four-letter type entirely. That's not really a measurement bug so much as a predictable consequence of forcing a binary split on traits that mostly don't distribute as two separate humps: most people sit closer to the middle of most dimensions than to either extreme, which means small shifts in mood or mindset when answering are enough to tip a near-50/50 respondent across the line. A continuous score doesn't have a line to tip across — landing near the midpoint is simply the result, stable across retests in a way a forced letter can't be.
What this means for a result you're actually going to use
A binary type is easy to remember and easy to share — that's a real part of MBTI's popularity, not a coincidence. But it costs you the exact information a mid-range score is built to carry: that a trait is context-dependent rather than absent or muted. Bearing's report keeps that distinction because "this shows up sometimes" and "this doesn't show up" are different, useful, separately actionable pieces of information — collapsing them into one convenient letter isn't a simplification, it's a loss.
Bearing's assessment scores all 30 IPIP-NEO facets on a continuous scale, with mid-range results reported as their own specific finding — not rounded toward a type.
Sources: Pittenger, D. J. (2005). Cautionary comments regarding the Myers-Briggs Type Indicator. Consulting Psychology Journal: Practice and Research, 57(3), 210–221.