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Table 6 Properties of point estimates of the treatment effect from Models A - E in scenarios 4 to 6

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 4 - chance imbalance, 45 centres each with 4 subjects

A

0.502

(0.146)

0.150

0.021

0.511

(0.154)

0.154

0.024

0.494

(0.168)

0.166

0.028

B

0.506

(0.162)

0.172

0.026

0.510

(0.174)

0.172

0.030

0.496

(0.180)

0.172

0.032

C

0.502

(0.145)

0.149

0.021

0.511

(0.155)

0.152

0.024

0.496

(0.165)

0.159

0.027

D

0.501

(0.146)

0.146

0.021

0.511

(0.155)

0.149

0.024

0.496

(0.165)

0.155

0.027

E-1

0.492

(0.525)

0.122

0.275

0.504

(0.544)

0.126

0.296

0.481

(0.482)

0.127

0.232

E-2

0.506

(0.274)

0.265

0.075

0.515

(0.284)

0.269

0.081

0.490

(0.285)

0.260

0.081

Scenario 5 - chance imbalance, 18 centres each with 10 subjects

A

0.495

(0.148)

0.150

0.022

0.498

(0.150)

0.153

0.023

0.497

(0.169)

0.166

0.028

B

0.494

(0.156)

0.157

0.024

0.498

(0.152)

0.157

0.023

0.500

(0.161)

0.157

0.026

C

0.495

(0.148)

0.150

0.022

0.498

(0.149)

0.151

0.022

0.499

(0.159)

0.153

0.025

D

0.494

(0.148)

0.142

0.022

0.498

(0.150)

0.144

0.022

0.499

(0.159)

0.148

0.025

E-1

0.488

(0.206)

0.130

0.042

0.498

(0.199)

0.130

0.039

0.503

(0.204)

0.130

0.042

E-2

0.490

(0.177)

0.163

0.031

0.501

(0.172)

0.162

0.030

0.501

(0.178)

0.164

0.032

Scenario 6 - chance imbalance, 6 centres each with 30 subjects

A

0.499

(0.153)

0.149

0.023

0.502

(0.150)

0.153

0.022

0.510

(0.165)

0.164

0.027

B

0.499

(0.155)

0.150

0.024

0.501

(0.150)

0.151

0.022

0.507

(0.151)

0.152

0.023

C

0.499

(0.153)

0.149

0.024

0.503

(0.149)

0.150

0.022

0.507

(0.151)

0.151

0.023

D

0.498

(0.154)

0.129

0.024

0.503

(0.150)

0.131

0.022

0.508

(0.151)

0.134

0.023

E-1

0.498

(0.159)

0.146

0.025

0.502

(0.156)

0.146

0.024

0.507

(0.157)

0.146

0.025

E-2

0.498

(0.157)

0.165

0.025

0.502

(0.153)

0.164

0.023

0.507

(0.154)

0.167

0.024

  1. SD: empirical standard deviation; Ave. SE: average estimated SE; MSE: mean squared error; ICC: intraclass (intracentre) correlation