Criterion validity of a computer-based tutorial for teaching waist circumference self-measurement.

Knowing one's waist circumference (WC) is a primary step in assessing risk of disease and health disorders. One concern, however, is the accuracy with which WC measurements are taken. This study attempted to determine the effectiveness of a computer-based tutorial (CBT) in teaching previously untrained individuals to properly self-measure WC. Eighty-three subjects used the CBT to learn and perform WC self-measurement. Validity of the subjects' measurements was determined by comparing their measurements to a traditionally trained and experienced tester's. Bland-Altman and Box-Whisker comparisons revealed an average 1.57cm bias in the subjects' WC measurements. Bland-Altman bias plots illustrated agreement between the subjects' and experienced tester's measurements. Pearson correlation (r=0.97) showed no significant (p<0.0001) difference between the two groups. The results of this experiment suggest that the tested CBT is efficacious in teaching WC self-measurement. The tutorial could be used in the areas of health assessment, standardization, biomedical education and research.