Table 1 Intraclass correlation coefficient (ICC) calculations (with 95% confidence intervals) for continuous outcome measurements at data downloads between September 2008 and May 2010
From: Ongoing monitoring of data clustering in multicenter studies
Measurement | ICCs (95% CI) by date of data download | |||
|---|---|---|---|---|
| Â | 9/08 | 3/09 | 10/09 | 05/10 |
| Â | n = 1,572 15 clinics | n = 4,865 27 clinics | n = 8,949 31 clinics | n = 12 374 31 clinics |
Standing height | 0.06 (0.01, 0.11) | 0.03 (0.01, 0.06) | 0.03 (0.01, 0.05) | 0.03 (0.02, 0.05) |
Sitting height | 0.92 (0.86, 0.97) | 0.28 (0.17, 0.39) | 0.03 (0.01, 0.04) | 0.03 (0.01, 0.05) |
Weight | 0.03 (0.00, 0.06) | 0.02 (0.00, 0.03) | 0.02 (0.01, 0.03) | 0.02 (0.01, 0.03) |
Bioimpedance | 0.005 (0.00, 0.01) | 0.004 (0.00, 0.01) | 0.01 (0.00, 0.01) | 0.01 (0.00, 0.02) |
Mid-upper arm circumference | 0.04 (0.00, 0.08) | 0.02 (0.01, 0.04) | 0.03 (0.01, 0.05) | 0.03 (0.01, 0.05) |
Systolic blood pressure | 0.16 (0.05, 0.26) | 0.11 (0.05, 0.17) | 0.12 (0.06, 0.17) | 0.12 (0.06, 0.17) |
Waist circumference | 0.10 (0.02, 0.18) | 0.10 (0.05, 0.15) | 0.09 (0.05, 0.14) | 0.07 (0.04, 0.11) |
Hip circumference | 0.05 (0.00, 0.10) | 0.04 (0.01, 0.06) | 0.03 (0.01, 0.05) | 0.03 (0.01, 0.05) |
Head circumference | 0.02 (0.00, 0.05) | 0.05 (0.02, 0.08) | 0.13 (0.07, 0.19) | 0.10 (0.06, 0.15) |
Triceps skinfold thickness | 0.09 (0.02, 0.16) | 0.07 (0.03, 0.11) | 0.11 (0.06, 0.17) | 0.12 (0.07, 0.18) |
Subscapular skinfold thickness | 0.07 (0.01, 0.13) | 0.04 (0.02, 0.07) | 0.04 (0.02, 0.06) | 0.04 (0.02, 0.06) |
Glucose | 0.05 (0.01, 0.09) | 0.08 (0.03, 0.13) | 0.09 (0.04, 0.13) | 0.08 (0.04, 0.11) |