Clarifications about taxometric method

Taxometrics is a statistical procedure for determining whether relationships among observables reflect the existence of a latent taxon (type, species, category, disease entity). A formal-numerical definition is needed because intuitive, commonsense notions of “carving nature at its joints” or “identifying natural kinds” cannot resolve disagreements as to taxonic reality for hard cases. Specific etiology (e.g., major gene, germ, traumatic event) is often unknown and is not appropriate in nonmedical domains. Lacking an infallible criterion, the taxonic inference relies on the internal configural relations among the conjectural fallible indicators. An essential feature is multiple consistency tests that will not be satisfied if the latent structure is not taxonic or the parameters are badly estimated. Common misconceptions are that the taxon must be “sharply” distinguished, quantitative indicators must be bimodal, the causal origin must be biological, emergence of a large dimensional factor refutes taxonicity, and adopting a taxon is a mere matter of convention or preference.