Table 3.
| Impact of Group Size = 2 on Model with Individual-Level Covariate – DMV Study Data – Linear Random Effects Model | ||||||
|---|---|---|---|---|---|---|
| % of Tracts with 2 per Tract
|
||||||
| n=4 to 1549, average=447 a | 90 | 75 | 50 | 25 | 10 | |
|
|
||||||
| Intercept | 23.52 | 23.57 (23.24–23.90) | 23.50 (23.30–23.70) | 23.53 (23.39–23.67) | 23.52 (23.45–23.59) | 23.52 (23.48–23.56) |
| Standard error | 0.061 | 0.15 (0.142–0.165) | 0.11 (0.10–0.12) | 0.08 (0.08–0.09) | 0.07 (0.066–0.073) | 0.06 (0.063–0.065) |
| Age | 0.05 | 0.05 (0.044–0.055) | 0.05 (0.047–0.053) | 0.050 (0.048–0.052) | 0.05 (0.049–0.051) | 0.05 (0.050–0.051) |
| Standard error | 0.0007 | 0.002 (0.0020–0.0024) | 0.0014 (0.0013–0.0015) | 0.001 (0.0009–0.0010) | 0.0008 (0.00078–0.00086) | 0.0007 (0.00074–0.00077) |
| Random Effects | ||||||
| Variance between tract intercepts | 1.23 | 1.27 (0.78–1.76) | 1.26 (0.10–1.53) | 1.24 (1.09–1.38) | 1.22 (1.14–1.30) | 1.23 (1.18–1.28) |
| Variance within tracts | 23.97 | 23.94 (22.15–25.73) | 23.93 (23.02–24.84) | 24.00 (23.50–24.50) | 23.97 (23.59–24.35) | 23.97 (23.79–24.16) |
| ICC% | 4.89 | 5.05 (3.08–7.02) | 5.01 (3.92–6.07) | 4.90 (4.34–5.46) | 4.86 (4.54–5.18) | 4.88 (4.70–5.07) |
| Impact of Group Size = 2 on Model with Individual-Level Covariate – DMV Study Data – Logistic Random Effects Model | ||||||
|---|---|---|---|---|---|---|
| % of Tracts with 2 per Tract
|
||||||
| n=4 to 1549, average=447 a | 90 | 75 | 50 | 25 | 10 | |
|
|
||||||
| Intercept | 0.27 | 0.27 (0.24–0.30) | 0.27 (0.25–0.29) | 0.27 (0.26–0.28) | 0.27 (0.26–0.29) | 0.27 (0.267–0.275) |
| Standard error | 0.0052 | 0.014 (0.013–0.015) | 0.0098 (0.009–0.010) | 0.0072 (0.0069–0.0075) | 0.0060 (0.0057–0.0062) | 0.0055 (0.0054–0.0056) |
| Age | 0.0052 | 0.0051 (0.004–0.006) | 0.0052 (0.0049–0.0054) | 0.0051 (0.0050–0.0053) | 0.0052 (0.0051–0.0052) | 0.0052 (0.0051–0.0052) |
| Standard error | 0.000071 | 0.00022 (0.00020–0.00024) | 0.00014 (0.00013–0.00015) | 0.0001 (9.76E-05-0.0001) | 0.000082 (7.84E-05-8.55E-05) | 0.000075 (7.33E-05-7.62E-05) |
| Random Effects | ||||||
| Variance between tract intercepts | 0.0078 | 0.0077 (0.0048–0.011) | 0.0079 (0.0062–0.0095) | 0.0078 (0.0068–0.0088) | 0.0077 (0.0072–0.0083) | 0.0079 (0.0074–0.0081) |
| Variance within tracts | 0.2374 | 0.24 (0.234–0.240) | 0.24 (0.236–0.239) | 0.24 (0.236–0.238) | 0.24 (0.237–0.238) | 0.24 (0.237–0.238) |
| ICC% b | 0.24 | 0.23 (0.234–0.240) | 0.24 (0.188–0.289) | 0.24 (0.206–0.266) | 0.23 (0.22–0.25) | 0.24 (0.23–0.25) |
| Median Odds Ratio (MOR) b | 1.08 | 1.09 (1.07–1.10) | 1.09 (1.08–1.1) | 1.09 (1.08–1.09) | 1.09 (1.08–1.09) | 1.09 (1.08–1.09) |
a
Based on full sample of individuals included in study, range and average per tract. Other individuals per tract (group size) randomly selected and columns represent average estimates over 100 samples for each condition (e.g., 10% tracts with n per tract).
b
ICC with individual-level variance calculated using the formula of Snijders based on an underlying continuous variable with Vindividual = Π2 / 3 (Snijders and Bosker, 1999). Because of limitations of the ICC for non-linear outcomes, the Median Odds Ratio (MOR) (Merlo et al., 2004) was also calculated.