Table 4 |
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|
Simulation results based on 1,000 replications |
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|
Scenario 2.1*** Number of second-phase subjects: 300 cases 300 controls |
Scenario 2.2 Number of second-phase subjects: 400 cases 200 controls |
Scenario 2.3 Number of second- phase subjects: 200 cases 400 controls |
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|
|
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|
True OR†† |
OR* |
SD* |
Ef** |
OR* |
SD* |
Ef** |
OR* |
SD* |
Ef** |
|
|
|
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|
Individual-level information on all subjects † |
1.50 |
1.50 |
0.12 |
100 |
1.49 |
0.12 |
100 |
1.50 |
0.12 |
100 |
|
3.00 |
3.00 |
0.11 |
100 |
3.02 |
0.12 |
100 |
3.02 |
0.12 |
100 |
|
|
Method 3‡ |
1.50 |
1.50 |
0.22 |
29 |
1.49 |
0.23 |
27 |
1.52 |
0.22 |
30 |
|
3.00 |
2.98 |
0.21 |
29 |
2.97 |
0.21 |
30 |
3.05 |
0.20 |
35 |
|
|
Method 4‡ |
1.50 |
1.50 |
0.20 |
37 |
1.51 |
0.18 |
46 |
1.51 |
0.21 |
34 |
|
3.00 |
3.01 |
0.17 |
44 |
3.02 |
0.16 |
51 |
3.04 |
0.17 |
46 |
|
|
|
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|
* Geometric mean of the OR estimates and the empiric standard deviation of the ln(OR) estimates. ** Efficiency of the ln(OR) estimates. eff1 = (var(ln(OR1)) + (ln(true OR1))-ln(OR1)))/(var(ln(ORref)) + (ln(true ORref))-ln(ORref))) where ORref is the estimate in the ideal scenario. Efficiencies calculated when varying the number of second-phase cases and controls. The number of first-phase cases and controls are held fixed at 1,200 cases and 1,200 controls. *** These results are also presented in table 3 (scenario 2). † Ideal scenario. ‡ Methods 3–4 are further described in the Methods section and in Table 1. †† A confounder with OR = 2 is introduced and a positive bias-effect of 20% for OR = 1.50 and 33% for OR = 3.00 |
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|
Oudin et al. Environmental Health 2007 6:34 doi:10.1186/1476-069X-6-34 |
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