Table 1

Expected change in precision for 67 × 3, 33 × 6 and 30 × 7 designs compared with 30 × 30 design

30 × 30
design
Observed
DEFF
 Rho
 67 × 3 design
 33 × 6 design
 30 × 7 design




Expected
DEFF
Change
in the
width of the
CI,1
%
 Expected
DEFF
Change
in the
width of
the CI,1
%
 Expected
DEFF
Change
in the
width of
the CI,1
%
1
 0
 1
 +111.6
 1
 +113.2
 1
 +107.0
1.25
 0.0086
 1.0172
 +90.9
 1.0431
 +94.7
 1.0517
 +89.9
1.5
 0.01724
 1.0345
 +75.7
 1.0862
 +81.4
 1.1034
 +77.6
2
 0.03448
 1.0690
 +54.7
 1.1724
 +63.2
 1.2069
 +60.8
2.5
 0.05172
 1.1034
 +40.6
 1.2586
 +51.3
 1.3103
 +49.9
3
 0.06897
 1.1379
 +30.3
 1.3448
 +42.7
 1.4138
 +42.1
4
 0.10345
 1.2069
 +16.2
 1.5172
 +31.3
 1.6207
 +31.8
5
 0.13793
 1.2759
 +6.9
 1.6897
 +23.9
 1.8276
 +25.2
7
 0.20690
 1.4138
 -4.9
 2.0345
 +14.9
 2.2414
 +17.1
10
 0.31034
 1.6207
 -14.8
 2.5517
 +7.7
 2.8621
 +10.8

1 Relative expected change in the width of the 95% confidence interval compared to the 30 × 30 design

Bilukha Emerging Themes in Epidemiology 2008 5:7   doi:10.1186/1742-7622-5-7