Table 1.

Example Trial and Status of Imbalance and Proposed Randomization Vectors with Treatment Assignments

Patient Number	Hydroxyurea	ED Utilization	Placebo Proportion Prior to Randomization	Hydroxyurea Imbalance	Moderate ED Imbalance	High ED Imbalance	Overall Weighted Imbalance	Randomization Vector (Probability of placebo)	Assignment
1	Taking	Moderate	0*	0	0	0	0	0.33*	Treatment
2	Not Taking	High	0*	−1.00	−1.00	1.00	−1.00	0.33*	Placebo
3	Taking	Low	0.50	−0.50	−1.00	0.50	−0.75	0.19	Placebo
4	Taking	Moderate	0.67	−0.50	−1.00	0.50	−0.75	0.11	Treatment
5	Taking	Moderate	0.50	−0.33	−0.67	0.33	−0.50	0.19	Placebo
6	Taking	Moderate	0.60	−0.33	−0.67	0.33	−0.50	0.14	Treatment
7	Not Taking	Moderate	0.50	−0.08	−0.67	0.33	−0.25	0.19	Treatment
8	Not Taking	High	0.43	0.07	−0.47	0.13	−0.10	>0.01	Treatment
9	Taking	High	0.38	0	−0.33	0	−0.17	0.16	Treatment
10	Not Taking	Moderate	0.33	0.10	−0.38	0.05	−0.07	0.51	Treatment
11	Not Taking	Moderate	0.30	0.17	−0.42	0.08	0	0.78	Treatment
12	Not Taking	Moderate	0.27	0	−0.25	0	−0.13	0.91	Placebo
13	Taking	Low	0.33	−0.06	−0.17	0.03	−0.13	>0.01	Treatment
14	Taking	High	0.31	0.04	−0.27	0.18	0	0.51	Placebo
15	Not Taking	Moderate	0.36	0.10	−0.30	0.20	0.05	0.51	Treatment
16	Not Taking	Low	0.33	0.15	−0.24	0.22	0.14	0.16	Treatment
17	Taking	Moderate	0.31	0.21	−0.14	0.15	0.22	0.51	Placebo
18	Not Taking	Low	0.35	0.12	−0.21	0.10	0.06	0.51	Placebo
19	Taking	Moderate	0.39	0.07	−0.24	0.12	0.01	0.01	Treatment
20	Taking	Moderate	0.37	0.03	−0.26	0.13	−0.03	0.33	Treatment
21	Taking	High	0.35	0	−0.21	0.07	−0.07	0.01	Treatment
22	Taking	Low	0.33	−0.03	−0.17	0.09	−0.07	0.33	Treatment
23	Taking	Low	0.32	−0.05	−0.13	0.10	−0.07	0.33	Treatment
24	Not Taking	Low	0.30	−0.02	−0.10	0.11	−0.01	0.01	Treatment
25	Taking	Moderate	0.29	0.04	−0.03	0.07	0.06	0.33	Placebo
26	Taking	Moderate	0.32	0.01	−0.06	0.08	0.03	0.01	Treatment
27	Taking	Moderate	0.31	0.06	0	0.06	0.08	0.33	Placebo
28	Taking	Moderate	0.33	0.04	−0.02	0.06	0.06	>0.01	Treatment
29	Not Taking	Moderate	0.32	−0.03	0.02	0.04	0	0.78	Placebo
30	Not Taking	High	0.34	0	0.05	0	0.03	0.33	Treatment
31	Not Taking	High	0.33	−0.05	0	0.07	−0.02	0.33	Placebo
32	Taking	Low	0.35	−0.07	0.02	0.08	−0.02	0.51	Treatment
33	Taking	Low	0.34	−0.04	−0.02	0.06	−0.02	0.78	Placebo
34	Taking	Moderate	0.36	−0.05	−0.05	0.07	−0.04	0.33	Treatment
35	Taking	Low	0.35	−0.07	−0.02	0.08	−0.04	0.33	Treatment
36	Not Taking	High	0.34	−0.04	0	0.04	−0.02	>0.01	Treatment
37	Not Taking	Moderate	0.33	−0.09	0.04	0.02	−0.06	0.16	Placebo
38	Not Taking	Moderate	0.35	−0.06	0.02	0.03	−0.04	>0.01	Treatment
39	Taking	Moderate	0.34	−0.08	0	0.04	−0.06	0.16	Treatment
40	Taking	Low	0.33	−0.09	0.02	0.05	−0.06	0.51	Treatment
41	Taking	High	0.33	−0.10	0.04	0.02	−0.08	0.16	Treatment
42	Taking	Low	0.32	−0.12	0.06	0.02	−0.08	0.78	Treatment
43	Taking	Low	0.31	−0.08	0.02	0.01	−0.07	0.91	Placebo
44	Taking	Low	0.33	−0.06	−0.02	−0.01	−0.07	0.51	Placebo
45	Taking	High	0.34	−0.07	0	−0.03	−0.08	0.51	Treatment

The progress and treatment allocation decisions of the single example trial. Weighted overall imbalance is the sum of the hydroxyurea imbalance and one half times the sum of the moderate and high ED imbalances.

^*The first two patients are enrolled with a 1/3 probability of placebo.