Fitzpatrick Scale
Definition
A skin-tone classification system originally developed by dermatologist Thomas B. Fitzpatrick in 1975 (initially covering four types for UV response in phototherapy), expanded to the current six-category scale in 1988. Used in Gender Shades and subsequent studies as a proxy for skin tone in the absence of self-identified racial categorisation data.
- Originator
- Dermatologist Thomas B. Fitzpatrick
- Original year
- 1975, four types
- Current form
- Six-category scale from 1988
- Original purpose
- UV response classification for phototherapy
- Forensic reuse
- Skin-tone proxy in face and fingerprint bias studies such as Gender Shades
Common questions
Why is the Fitzpatrick scale considered an imperfect proxy for demographic fairness testing?+
It was designed to classify skin response to UV exposure for dermatology, not to represent racial or ethnic identity. Studies reuse it because self-identified race data is often unavailable, but the scale can group people of different backgrounds into the same category or split similar skin tones across categories.
How is the Fitzpatrick scale applied in studies like Gender Shades?+
Researchers annotate face images by Fitzpatrick category and compare a biometric system's error rate across those categories, using the pattern of higher errors on darker skin types as evidence of disparate performance even without direct race labels.
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