Intra-observer and Inter-observer Reliability in Direct Anthropometry

This study aimed to evaluate the reliability factors, and identify causes of error in direct anthropometry method. After training three beginner anthropometrists and following the instructions of anthropometric standards, 48 body dimensions of 42 male students were measured three times. In other words, the physical dimensions of each subject were measured for 9 times. All participants were wearing uniforms during anthropometry, with bare feet. Differences in values of Repeated Measurement Test were explored using SPSS software version 11. The same software was employed to evaluate, through calculating ICC index, the correlation between anthropometrists. Inter-observer repeated measurement test showed significant difference in the measurements taken in 3, 7 and 1 dimension(s) by the three anthropometrists. The average measurement was significantly different at 16 dimensions; this, however, showed no difference at 32 dimensions. Measurements taken by anthropometrist 1 had ICC values of 0.26 (Min) and 0.99 (Max); these values were 0.48 (Min) and 1.00 (Max) for anthropometrist 2 and 0.23 (Min) and 0.98 (Max) for antropometrist 3. The maximum and minimum values of ICC index in all three anthropometrists were respectively close to and above 0.98, and lower than 0.5. High value of ICC in the measured dimensions indicated high reliability of repeated measurements. The decreasing value of some indexes can be attributed to such factors as random error, poor design of measurements tool (which in turn leads to random error), the long time devoted to measurement process, high number of dimension measured, changes in posture of subjects and deviation from the standard position.