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Table 3 Treatment balancing properties of 1:2 sequence balance minimisation with 1 to 10 prognostic factors with 2levels, treatment totals weighted as zero, sample size 30, 60 and 120, random element = 0.95 to 0.5

From: Sequence balance minimisation: minimising with unequal treatment allocations

Random element

 

Number of factors

1

2

3

4

5

6

7

8

9

10

Sample size (n = 30), the expected number of participants allocated to the treatment with smallest-allocation ratio (n = 10)

p = 0.5

Mean (SE)

10.7 (0.07)

10.5 (0.04)

10.2 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.04)

10.1 (0.03)

10.1 (0.03)

10.1 (0.04)

 

Median (p1–p99)

11 (6–16)

10 (7.5–14)

10 (8–13)

10 (7–13)

10 (8–13)

10 (8–13)

10 (7–13)

10 (8–13)

10 (8–13)

10 (8–13)

p = 0.6

Mean (SE)

10.6 (0.06)

10.4 (0.04)

10.2 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.04)

10.1 (0.04)

10.1 (0.04)

 

Median (p1–p99)

11 (6–15)

10 (8–13)

10 (8–13)

10 (8–12.5)

10 (8–12)

10 (8–13)

10 (8–13)

10 (7–13)

10 (7–13)

10 (8–13)

p = 0.7

Mean (SE)

10.5 (0.05)

10.3 (0.03)

10.2 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.04)

10.1 (0.03)

 

Median (p1–p99)

10 (7–14)

10 (8–13)

10 (8–12.5)

10 (8–13)

10 (7.5–12)

10 (8–13)

10 (8–13)

10 (8–13)

10 (7.5–13)

10 (7.5–13)

p = 0.8

Mean (SE)

10.3 (0.04)

10.2 (0.03)

10.1 (0.03)

10.1 (0.03)

10.0 (0.03)

10.1 (0.03)

10.1 (0.03)

10.0 (0.03)

10.1 (0.04)

10.1 (0.03)

 

Median (p1–p99)

10 (7–14)

10 (8–13)

10 (8–13)

10 (8–13)

10 (8–12)

10 (8–13)

10 (8–12.5)

10 (7.5–12.5)

10 (8–13)

10 (8–13)

p = 0.85

Mean (SE)

10.3 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.03)

10.0 (0.03)

10.1 (0.03)

10.1 (0.03)

10.0 (0.03)

10.1 (0.04)

10.1 (0.03)

 

Median (p1–p99)

10 (8–13)

10 (8–12)

10 (8–12)

10 (8–12)

10 (8–12)

10 (8–13)

10 (8–13)

10 (8–13)

10 (7.5–13)

10 (7–13)

p = 0.9

Mean (SE)

10.1 (0.03)

10.1 (0.03)

10.0 (0.03)

10.0 (0.03)

10.1 (0.03)

10.1 (0.03)

10.0 (0.03)

10.1 (0.03)

10.1 (0.03)

10.0 (0.03)

 

Median (p1–p99)

10 (8–13)

10 (8–12)

10 (8–12)

10 (8–12)

10 (8–12)

10 (8–13)

10 (8–13)

10 (8–13)

10 (7.5–12)

10 (8–13)

p = 0.95

Mean (SE)

10.1 (0.02)

10.1 (0.03)

10.0 (0.03)

10.0 (0.03)

10.0 (0.03)

10.0 (0.03)

10.0 (0.03)

10.1 (0.03)

10.1 (0.03)

10.1 (0.04)

 

Median (p1–p99)

10 (9–12)

10 (8–12)

10 (8–12)

10 (8–12)

10 (8–12)

10 (7.5–12)

10 (8–12.5)

10 (8–12)

10 (7.5–13)

10 (8–13)

Sample size (n = 60), the expected number of participants allocated to the treatment with smallest-allocation ratio (n = 20)

p = 0.5

Mean (SE)

21.3 (0.09)

21.0 (0.07)

20.8 (0.06)

20.6 (0.05)

20.3 (0.05)

20.1 (0.05)

20.2 (0.05)

20.1 (0.05)

20.0 (0.05)

20.1 (0.05)

Median (p1–p99)

21 (14–29)

21 (16.5–26)

21 (17–25.5)

21 (17–25)

20 (17–24)

20 (17–24)

20 (17–24)

20 (17–23)

20 (17–23.5)

20 (17–24)

p = 0.6

Mean (SE)

21.1 (0.08)

20.9 (0.06)

20.7 (0.06)

20.4 (0.05)

20.3 (0.05)

20.2 (0.04)

20.1 (0.05)

20.0 (0.05)

20.1 (0.05)

20.2 (0.05)

 

Median (p1–p99)

21 (15–27)

21 (17–26)

21 (17–25)

20 (17–24)

20 (17–24)

20 (17–24)

20 (17–24)

20 (17–23)

20 (17–24)

20 (17–24)

p = 0.7

Mean (SE)

20.8 (0.07)

20.7 (0.05)

20.5 (0.05)

20.3 (0.05)

20.3 (0.05)

20.1 (0.05)

20.1 (0.05)

20.1 (0.05)

20.1 (0.05)

20.2 (0.05)

Median (p1–p99)

21 (16–26)

21 (17–24.5)

20 (17–25)

20 (17–24)

20 (17–24)

20 (17–24)

20 (17–24)

20 (17–24)

20 (16.5–24)

20 (16.5–24)

p = 0.8

Mean (SE)

20.5 (0.06)

20.4 (0.05)

20.5 (0.05)

20.2 (0.04)

20.1 (0.05)

20.1 (0.05)

20.1 (0.05)

20.0 (0.05)

20.2 (0.05)

20.1 (0.05)

 

Median (p1–p99)

21 (17–25)

20 (17–24)

20 (17–24)

20 (17–24)

20 (17–23)

20 (17–23.5)

20 (17–24)

20 (17–23)

20 (17–24)

20 (16–24)

p = 0.85

Mean (SE)

20.5 (0.05)

20.3 (0.04)

20.2 (0.05)

20.3 (0.04)

20.2 (0.04)

20.1 (0.04)

20.2 (0.05)

20.0 (0.05)

20.1 (0.05)

20.2 (0.05)

 

Median (p1–p99)

20 (17–24)

20 (17–23.5)

20 (17–24)

20 (17–24)

20 (17–23)

20 (17–23.5)

20 (17–23.5)

20 (17–23)

20 (17–24)

20 (17–24)

p = 0.9

Mean (SE)

20.2 (0.04)

20.2 (0.04)

20.3 (0.05)

20.2 (0.04)

20.2 (0.04)

20.0 (0.05)

20.1 (0.05)

20.2 (0.05)

20.1 (0.05)

20.1 (0.05)

 

Median (p1–p99)

20 (17.5–23)

20 (17–23)

20 (17–24)

20 (17–23)

20 (17–23)

20 (17–24)

20 (17–24)

20 (17–24)

20 (17–24)

20 (17–24)

p = 0.95

Mean (SE)

20.1 (0.03)

20.1 (0.03)

20.2 (0.04)

20.1 (0.04)

20.1 (0.04)

20.0 (0.04)

20.1 (0.05)

20.1 (0.05)

20.0 (0.04)

20.3 (0.05)

 

Median (p1–p99)

20 (18–23)

20 (18–23)

20 (17–23)

20 (17–23)

20 (17–23)

20 (17–23)

20 (16.5–23)

20 (17–23)

20 (17–24)

20 (17–24)

Sample size (n = 120), the expected number of participants allocated to the treatment with smallest-allocation ratio (n = 40)

p = 0.5

Mean (SE)

42.2 (0.13)

41.7 (0.10)

41.1 (0.08)

40.7 (0.07)

40.4 (0.07)

40.3 (0.07)

40.4 (0.07)

40.3 (0.07)

40.3 (0.07)

40.3 (0.07)

 

Median (p1–p99)

42 (33–52)

42 (35–49)

41 (35–47)

41 (35–46)

40 (36–46)

40 (35–45)

40 (35–46)

40 (36–46)

40 (35–45)

40 (35–45.5)

p = 0.6

Mean (SE)

41.8 (0.12)

41.6 (0.09)

40.8 (0.07)

40.5 (0.07)

40.4 (0.07)

40.5 (0.07)

40.3 (0.07)

40.3 (0.07)

40.3 (0.07)

40.4 (0.07)

 

Median (p1–p99)

42 (33–50)

41 (35–48)

41 (35–47)

40 (36–45)

40 (36–45)

40 (36–46)

40 (35–45)

40 (35–46)

40 (35–45)

40 (35–46)

p = 0.7

Mean (SE)

41.4 (0.10)

41.2 (0.08)

40.7 (0.07)

40.5 (0.07)

40.3 (0.07)

40.4 (0.07)

40.4 (0.07)

40.3 (0.07)

40.2 (0.07)

40.1 (0.07)

 

Median (p1–p99)

41 (34–49)

41 (35–47)

41 (36–46)

41 (35–46)

40 (35.5–45)

40 (35–46)

40 (35–45)

40 (35–46)

40 (36–45)

40 (36–46)

p = 0.8

Mean (SE)

40.8 (0.08)

40.8 (0.07)

40.6 (0.07)

40.4 (0.07)

40.3 (0.07)

40.2 (0.07)

40.3 (0.07)

40.3 (0.07)

40.4 (0.07)

40.3 (0.07)

 

Median (p1–p99)

41 (35.5–46)

41 (35–46)

41 (35–46)

40 (35–45)

40 (35–45)

40 (35–45)

40 (35–46)

40 (35–46)

40 (35–45)

40 (35–45)

p = 0.85

Mean (SE)

40.7 (0.07)

40.5 (0.07)

40.5 (0.07)

40.3 (0.07)

40.2 (0.07)

40.3 (0.07)

40.2 (0.07)

40.3 (0.07)

40.3 (0.07)

40.2 (0.07)

 

Median (p1–p99)

41 (35–46)

40 (36–45)

40 (36–45)

40 (35.5–45)

40 (35.5–45)

40 (35–45)

40 (35–45.5)

40 (35–45)

40 (35–45)

40 (35–45)

p = 0.9

Mean (SE)

40.5 (0.06)

40.5 (0.06)

40.3 (0.06)

40.4 (0.07)

40.2 (0.07)

40.3 (0.07)

40.3 (0.07)

40.2 (0.07)

40.4 (0.07)

40.2 (0.07)

 

Median (p1–p99)

40 (36–45)

41 (36–45.5)

40 (36–45)

40 (35–45)

40 (35–45)

40 (35–45)

40 (35–45)

40 (35–45)

40 (35–45)

40 (35–45)

p = 0.95

Mean (SE)

40.3 (0.04)

40.3 (0.06)

40.2 (0.06)

40.2 (0.06)

40.2 (0.07)

40.4 (0.06)

40.2 (0.07)

40.2 (0.07)

40.3 (0.07)

40.3 (0.07)

 

Median (p1–p99)

40 (38–44)

40 (36–44)

40 (36–44)

40 (36–44.5)

40 (35.5–45)

40 (36–45)

40 (35–46)

40 (35–46)

40 (35–45)

40 (35–45)

  1. Summary statistics from 1000 simulations. Treatment balance under best case scenario: mean (se): 10 (0), 20 (0), 40 (0) and median (p1 – p99): 10 (10 - 10), 20 (20 – 20), 40 (40 – 40) for sample size 30, 60 and 120 respectively