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Table 2 Simulation results (30% censored; Scenario 2–Scenario 4)

From: A multiple imputation method based on weighted quantile regression models for longitudinal censored biomarker data with missing values at early visits

α

α 0

α 1

α 2

Method

Bias

100xRE

Bias

100xRE

Bias

100xRE

Scenario 2: MVN, Unstructured covariance

 

OMNI

0.0017

–

-0.0006

–

-0.0013

–

CC-DL/2

0.0527

16.527

-0.5413

7.541

0.1161

28.516

MI 1

0.1809

8.011

-0.3166

11.718

0.0028

18.080

MI 2

0.0183

42.410

-0.0014

21.517

-0.0035

52.201

MI-CQR

0.0433

63.613

-0.0050

36.069

-0.0089

69.551

MI-wCQR 1

0.0319

71.852

-0.0099

42.007

-0.0031

78.523

MI-wCQR 2

0.0204

71.104

-0.0299

40.525

0.0031

77.691

MI-wCQR 3

0.0172

63.936

-0.0168

37.197

0.0030

70.009

Scenario 3: MVE, Exchangeable covariance

 

OMNI

0.0028

–

0.0000

–

-0.0014

–

CC-DL/2

0.2094

12.616

-0.4212

7.660

0.0057

22.869

MI 1

0.4430

3.682

-0.6098

3.640

-0.0981

10.591

MI 2

0.0423

32.878

0.0008

11.074

-0.0088

44.840

MI-CQR

0.0667

58.224

-0.0183

36.201

-0.0128

71.372

MI-wCQR 1

0.0501

62.644

-0.0163

41.087

-0.0055

77.240

MI-wCQR 2

0.0379

62.214

-0.0256

40.690

0.0000

77.128

MI-wCQR 3

0.0273

59.215

-0.0041

37.352

0.0018

71.902

Scenario 4: MVE, Heteroscedastic covariance

 

OMNI

0.0028

–

0.0000

–

-0.0014

–

CC-DL/2

0.1739

14.389

-0.4081

8.210

0.0171

23.356

MI 1

0.1892

3.537

-0.3084

1.531

0.0002

10.432

MI 2

0.0410

32.650

0.0011

11.025

-0.0083

44.126

MI-CQR

0.0649

58.870

-0.0141

36.739

-0.0125

71.618

MI-wCQR 1

0.0492

63.492

-0.0121

41.733

-0.0054

78.362

MI-wCQR 2

0.0340

63.222

-0.0223

40.015

0.0009

78.325

MI-wCQR 3

0.0273

59.195

-0.0041

37.005

0.0018

71.929

  1. OMNI: Omniscient; CC-DL/2: CC with censored values imputed by DL/2; MI-MCMC 1: MI-MCMC imputing only missing values; MI-MCMC 2: MI-MCMC imputing both censored and missing values; MI-CQR: MI-unweighted CQR; MI-wCQR 1: MI-weighted CQR using original probability of missing; MI-wCQR 2: MI-weighted CQR using estimated probability from censored values imputed by DL/2; MI-wCQR 3MI-weighted CQR using estimated probability from uncensored values only; RE: Relative Efficiency