Measuring Skin Color: Consistency, Comparability, and Meaningfulness of Rating Scale Scores and Handheld Device Readings

Abstract As US society continues to diversify and calls for better measurements of racialized appearance increase, survey researchers need guidance about effective strategies for assessing skin color in field research. This study examined the consistency, comparability, and meaningfulness of the two most widely used skin tone rating scales (Massey–Martin and PERLA) and two portable and inexpensive handheld devices for skin color measurement (Nix colorimeter and Labby spectrophotometer). We collected data in person using these four instruments from forty-six college students selected to reflect a wide range of skin tones across four racial-ethnic groups (Asian, Black, Latinx, White). These college students, five study staff, and 459 adults from an online sample also rated forty stock photos, again selected for skin tone diversity. Our results—based on data collected under controlled conditions—demonstrate high consistency across raters and readings. The Massey–Martin and PERLA scale scores were highly linearly related to each other, although PERLA better differentiated among people with the lightest skin tones. The Nix and Labby darkness-to-lightness (L*) readings were likewise linearly related to each other and to the Massey–Martin and PERLA scores, in addition to showing expected variation within and between race ethnicities. In addition, darker Massey–Martin and PERLA ratings correlated with online raters’ expectations that a photographed person experienced greater discrimination. In contrast, the redness (a*) and yellowness (b*) undertones were highest in the mid-range of the rating scale scores and demonstrated greater overlap across race-ethnicities. Overall, each instrument showed sufficient consistency, comparability, and meaningfulness for use in field surveys when implemented soundly (e.g., not requiring memorization). However, PERLA might be preferred to Massey–Martin in studies representing individuals with the lightest skin tones, and handheld devices may be preferred to rating scales to reduce measurement error when studies could gather only a single rating.