Origin
The impostor phenomenon was first described by clinical psychologists Pauline Clance and Suzanne Imes (1978), based on their work with high-achieving women who, despite objective success, experienced persistent internal doubt about their competence and a fear of being exposed as a "fraud." Clance (1985) later developed the Clance Impostor Phenomenon Scale (CIPS), a 20-item self-report measure that remains the most widely used instrument for the construct.
What it measures
The construct captures three recurring features: the sense that one's success is undeserved or attributable to luck or error; fear of being unmasked as less capable than others believe; and difficulty internalising accomplishments. It is described as a phenomenon or experience rather than a clinical disorder — it does not appear as a diagnosis in the DSM.
Psychometric standing
The CIPS has shown good internal consistency and validity across numerous samples and has been studied in students, professionals, and across genders and cultures (Mak, Kleitman & Abbott, 2019, review). Research links impostor feelings to anxiety, lower self-esteem, and perfectionism.
Reviewers note measurement heterogeneity across the available scales and caution against treating the experience as a fixed trait.