Has anyone applied taxometric methods to motivational typologies beyond the Big Five framework?
The "pseudoscience" label gets applied to type-based personality models as a single verdict, but it seems to conflate three separable questions:
Do the described behavioral patterns actually exist as discrete clusters? This is an open empirical question for most typological systems. Not disproven; largely untested with appropriate methods.
Can the patterns be measured reliably? For the Enneagram specifically, cross-instrument agreement sits around 42%. This is a known measurement failure, but the failure appears to be format-specific. Self-report instruments hit a structural ceiling when the construct being measured shapes how respondents describe themselves. The Big Five's measurement advantage came partly from format alignment: the constructs were extracted from self-report data, so self-report instruments naturally recover them. Constructs not derived from self-report factor analysis may require different measurement formats entirely.
Has anyone studied them rigorously? For most typological systems outside the Big Five, the answer is almost entirely no. The absence is striking but it reads more as neglect than disconfirmation.
Nick Haslam's work on taxometric methods showed that categorical vs. dimensional structure is an empirically testable question, not a theoretical assumption. The methods exist to determine whether behavioral data clusters categorically. Whether anyone has systematically applied these methods to motivational typologies that describe behavioral patterns (rather than self-reported trait endorsements) is the question I keep running into.
The bridge position that seems unoccupied: the described patterns may be real, the dominant measurement approach may be structurally wrong for them, and better-suited methods exist in behavioral observation traditions that haven't been applied. This is different from both "the system works, trust the practitioners" and "it's pseudoscience, reject it entirely."
Has the community encountered taxometric or behavioral observation approaches applied to personality constructs outside the standard factor-analytic framework? Interested in what's actually being done, not what's theoretically possible.