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Table 4 Properties of point estimates of the treatment effect from Models A - E in scenarios 1 to 3

From: Comparing methods to estimate treatment effects on a continuous outcome in multicentre randomized controlled trials: A simulation study

  ICC = 0.01 ICC = 0.05 ICC = 0.20
Model Mean
effect
(SD) 		Ave.
SE 		MSE Mean
effect
(SD) 		Ave.
SE 		MSE Mean
effect
(SD) 		Ave.
SE 		MSE
Scenario 1 - balanced design, 45 centres each with 4 subjects
A 0.496
(0.148) 		0.149 0.022 0.499
(0.146) 		0.152 0.021 0.497
(0.151) 		0.167 0.023
B 0.496
(0.148) 		0.148 0.022 0.499
(0.146) 		0.148 0.021 0.497
(0.151) 		0.149 0.023
C 0.496
(0.148) 		0.147 0.022 0.499
(0.146) 		0.148 0.021 0.497
(0.151) 		0.149 0.023
D 0.496
(0.148) 		0.146 0.022 0.499
(0.146) 		0.146 0.021 0.497
(0.151) 		0.147 0.023
E-1 0.496
(0.494) 		0.066 0.244 0.491
(0.454) 		0.066 0.206 0.506
(0.447) 		0.065 0.200
E-2 0.499
(0.163) 		0.172 0.027 0.497
(0.166) 		0.170 0.027 0.494
(0.162) 		0.170 0.026
Scenario 2 - balanced design, 18 centres each with 10 subjects
A 0.490
(0.149) 		0.150 0.022 0.504
(0.155) 		0.152 0.024 0.498
(0.145) 		0.166 0.021
B 0.490
(0.149) 		0.149 0.022 0.504
(0.155) 		0.149 0.024 0.498
(0.145) 		0.149 0.021
C 0.490
(0.149) 		0.148 0.022 0.504
(0.155) 		0.148 0.024 0.498
(0.145) 		0.149 0.021
D 0.490
(0.149) 		0.142 0.022 0.504
(0.155) 		0.143 0.024 0.498
(0.145) 		0.142 0.021
E-1 0.490
(0.178) 		0.130 0.032 0.501
(0.180) 		0.130 0.032 0.498
(0.171) 		0.130 0.029
E-2 0.492
(0.164) 		0.154 0.027 0.503
(0.165) 		0.155 0.027 0.498
(0.158) 		0.153 0.025
Scenario 3 - balanced design, 6 centres each with 30 subjects
A 0.496
(0.149) 		0.149 0.022 0.492
(0.149) 		0.152 0.022 0.504
(0.151) 		0.164 0.023
B 0.496
(0.149) 		0.149 0.022 0.492
(0.149) 		0.149 0.022 0.504
(0.151) 		0.149 0.023
C 0.496
(0.149) 		0.149 0.022 0.492
(0.149) 		0.149 0.022 0.504
(0.151) 		0.149 0.023
D 0.496
(0.149) 		0.130 0.022 0.492
(0.149) 		0.130 0.022 0.504
(0.151) 		0.149 0.023
E-1 0.497
(0.153) 		0.144 0.023 0.491
(0.154) 		0.144 0.024 0.508
(0.156) 		0.144 0.024
E-2 0.497
(0.151) 		0.163 0.023 0.491
(0.151) 		0.163 0.023 0.507
(0.153) 		0.161 0.023
  1. SD: empirical standard deviation; Ave. SE: average estimated SE; MSE: mean squared error; ICC: intraclass (intracentre) correlation
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BMC Medical Research Methodology

ISSN: 1471-2288

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