Obtained from Photographs

The objective of this study was to evaluate agreement among counts of melanocytic nevi made by parents, counts made by a dermatologist, and counts made by assessment of photographs. In 1990, 421 schoolchildren aged 6–15 years from Townsville, Queensland, Australia (latitude 19.16˚S), participated in the Eastern Australian Childhood Nevus Study. In an agreement study, parents were asked to mark on an anatomic diagram any melanocytic nevi greater than or equal to 2 mm in diameter and greater than or equal to 5 mm in diameter they observed on their child’s back prior to the child’s examination by a dermatologist; 324 parents responded (a 77% response rate). Standardized slide photographs of each child’s back were taken, and melanocytic nevi were counted by an experienced non-medical-examiner upon projection. Agreement was assessed graphically and with the concordance correlation coefficient (r c). Parental counts of melanocytic nevi were similar to counts made by the dermatologist (n = 77; for nevi ≥2 mm, r c = 0.51; for nevi ≥5 mm, r c = 0.78) and counts obtained from the photographs (n = 324; for nevi ≥2 mm, r c = 0.68; for nevi ≥5 mm, r c = 0.68). Few parents reported false-positive lesions. Parents tended to underestimate the number of melanocytic nevi greater than or equal to 2 mm in diameter (mean difference from dermatologist: –3.2, standard deviation 6.8; mean difference from photographs: –1.1, standard deviation 5.1), particularly when the density of melanocytic nevi was high. Agreement between dermatologist counts and photograph counts was high (for nevi ≥2 mm, r c = 0.80; for nevi ≥5 mm,