Intrarater reliability and the value of real change for waist and hip circumference measures by a novice rater.

Intrarater reliability and measurement error associated with waist and hip circumference measures performed by a novice rater with one measurement were examined and compared among Body Mass Index (BMI) subgroups in a convenience sample of 76 participants (25 men, 51 women; M age = 47.2 yr., SD = 14.2). A rater blinded to the purpose of the study, as well as to the tape measure results, received training and then performed hip and waist circumference measures twice with a 10-min. interval. Intrarater reliability of the measures was acceptable (ICC3,1 > .95) across the BMI subgroups; measurement error was found to be greater in the overweight and obese subgroups. If a test-retest change score is greater than 3.0 cm in waist circumference and 2.0 cm in hip circumference, it can be assumed to be a true change with 95% confidence.