Table 2.
Randomization description
| Wave | Start month | Allocation ratio | Stratifying variables |
|---|---|---|---|
| Wave 1 |
Nov-04 |
3:1 |
Age category and gender |
| Wave 2 |
Dec-04 |
45:55 |
Age category, gender, and Medicare Advantage coverage flag |
| Wave 3 |
May-05 |
3:1 |
Gender, Medicare Advantage coverage flag and claims-based cluster variable* |
| Wave 4 | May-05 | 1:1 | Gender and claims-based cluster variable* |
*Developed with SAS fastclus procedure using predicted costs, inpatient admissions, ED and specialist visits in prior 12 months at time of randomization.