What the Evidence Says

The Enneagram is very widely used and very thinly evidenced, and both halves of that sentence are true. Reviews of the empirical literature have generally found that Enneagram inventories show some internal reliability and some correlation with established personality measures such as the five-factor model, but that the central structural claims of the system, that there are exactly nine types, that people belong to one of them, that the stress and growth arrows describe real movement, and that the wings function as described, are not supported by the available evidence and in several studies are contradicted by it.

Factor analyses of Enneagram instruments have not reliably recovered nine factors. This is not a fringe objection; it is the state of the published research. The system may still be found useful as a framework for reflection, and many people do, but it is not a validated psychometric instrument and should not be used as one in hiring or clinical decisions.