Table 2

Technical error of measurement between two repeat measurements of segmental length for non-standers taken 2–4 weeks apart

Number of paired measurements (n)Mean of paired measurementsDifference between
first and second measurement
Mean (95% CI)
P valuesTechnical error of measurement (CV)
Upper arm length (cm)2527.20.5 (−1.3 to 0.3)0.21.37 (5.03)
Tibial length (cm)2729.40.2 (−0.7 to 1.1)0.61.57 (5.35)
 Tibial length (cm) <12 years1726.8−0.23 (−0.97 to 0.51)0.261.00 (3.74)
Knee height (cm)2737.30.1 (−0.6 to 0.4)0.70.81 (2.18)
 Knee height (cm) <12 years1733.6−0.23 (−0.90 to 0.45)0.240.91 (2.72)
Supine length (cm)25126.00.3 (−1.1 to 1.8)0.62.47 (1.96)
 Supine length (cm) <12 years15116.4−0.058 (−1.19 to 1.08)0.461.39 (1.20)
  • TEM=√∑d2⁄2 n, where d is the difference between two measurements and n isthe number of measurements. CV: 100xTEM/mean of measurements taken, expressed as a percentage.