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Table 1 Bias, empirical standard error, mean square error, power and design effect of the biomarker regression coefficient estimate (\( {\hat{\beta}}_{BM} \)) for the full cohort and different sampling designs. Accuracy of surrogate: sensitivity (i.e. probability of having a positive surrogate if the biomarker is positive) = 0.7 and specificity (i.e. probability of having a negative surrogate if the biomarker is negative) = 0.7, biomarker common (a) and rare (b)

From: Sampling strategies to evaluate the prognostic value of a new biomarker on a time-to-event end-point

Sampling design

Stratification variable

n*

Bias

SE empirical

MSE

Power (%)

Design effect

Censoring rate

Censoring rate

Censoring rate

Censoring rate

Censoring rate

0

0.1

0.4

0

0.1

0.4

0

0.1

0.4

0

0.1

0.4

0

0.1

0.4

a)

Full cohort

–

2000

0.008

−0.015

0.009

0.093

0.095

0.112

0.009

0.009

0.013

99

97

95

–

–

–

1. SRS

–

600

0.004

−0.013

0.006

0.182

0.187

0.206

0.033

0.035

0.042

64

58

53

–

–

–

2. PPS

Event

599

0.007

−0.015

0.007

0.173

0.180

0.199

0.029

0.033

0.039

65

58

54

1.003

1.003

1.005

2a. PPS

Event; Risk factor

598

0.008

−0.016

0.004

0.172

0.175

0.205

0.029

0.031

0.042

65

58

52

1.002

1.003

1.002

2b. PPS

Event; Confounder

598

0.003

−0.015

0.002

0.174

0.179

0.203

0.030

0.032

0.041

65

57

51

0.999

1.002

1.000

2c. PPS

Event; Surrogate

598

0.007

−0.013

0.013

0.161

0.171

0.190

0.026

0.029

0.036

69

64

57

1.106

1.129

1.104

3. CC

Event

600

0.011

−0.008

0.019

0.159

0.158

0.179

0.025

0.025

0.032

74

68

67

1.179

1.219

1.352

3a. CC

Event; Risk factor

600

0.010

−0.009

0.008

0.162

0.166

0.182

0.026

0.028

0.033

72

65

62

1.139

1.176

1.307

3b. CC

Event; Confounder

600

0.012

−0.015

0.010

0.162

0.161

0.175

0.026

0.026

0.031

73

65

66

1.182

1.187

1.354

3c. CC

Event; Surrogate

600

0.008

−0.016

0.012

0.148

0.153

0.170

0.022

0.024

0.029

76

71

69

1.334

1.363

1.495

4. NCC

Event

550

0.008

−0.018

0.014

0.169

0.165

0.175

0.029

0.028

0.031

68

63

67

1.066

1.144

1.378

5. CM

Event; Surrogate

546

−0.044

−0.058

− 0.009

0.151

0.153

0.165

0.025

0.027

0.027

67

61

67

1.379

1.395

1.536

b)

Full cohort

–

2000

−0.028

−0.004

−0.023

0.193

0.199

0.225

0.038

0.039

0.052

52

53

41

–

–

–

1. SRS

–

600

−0.045

− 0.041

−0.093

0.376

0.392

0.802

0.144

0.156

0.652

23

23

19

–

–

–

2 PPS

Event

599

−0.051

−0.023

−0.060

0.380

0.394

0.453

0.147

0.155

0.209

25

24

19

1.079

1.131

1.139

2a. PPS

Event; Risk factor

598

−0.048

−0.039

− 0.081

0.372

0.393

0.721

0.141

0.156

0.526

22

24

21

1.085

1.109

1.145

2b. PPS

Event; Confounder

598

−0.057

−0.033

−0.059

0.381

0.393

0.453

0.148

0.156

0.209

23

23

20

1.077

1.104

1.140

2c. PPS

Event; Surrogate

598

−0.055

−0.022

− 0.073

0.388

0.391

0.597

0.153

0.153

0.362

24

25

19

1.090

1.147

1.158

3. CC

Event

600

−0.003

0.021

0.003

0.332

0.339

0.368

0.110

0.116

0.135

24

26

22

1.257

1.317

1.509

3a. CC

Event; Risk factor

600

−0.011

0.015

0.006

0.345

0.357

0.384

0.119

0.127

0.148

23

24

21

1.193

1.283

1.418

3b. CC

Event; Confounder

600

−0.023

0.024

0.011

0.328

0.344

0.363

0.108

0.119

0.132

23

26

22

1.267

1.329

1.513

3c. CC

Event; Surrogate

565

−0.018

0.011

−0.010

0.311

0.313

0.345

0.097

0.098

0.119

26

29

24

1.419

1.607

1.757

4. NCC

Event

545

−0.020

0.024

−0.000

0.354

0.355

0.363

0.126

0.127

0.132

21

24

21

1.126

1.222

1.513

5. CM

Event; Surrogate

529

−0.057

−0.041

−0.028

0.311

0.315

0.341

0.099

0.101

0.117

26

27

25

1.541

1.679

1.823

  1. Legend: SRS Simple Random Sample, PPS Probability Proportional to size, CC Case-Control, NCC Nested Case-Control, CM Counter-matching; n* mean sample size of the full cohort (first row) and of the phase II sample