Table 2.

| Description of restricted randomization methods

Method	Purpose
Permuted block	Ensure balance in sample size across randomization groups
Stratification	Ensure balance on stratification factors across randomization groups
Minimization	Balance several variables at once (including continuous variables, potentially), as well as sample size, across randomization groups

These approaches can be applied to both randomization to components and randomization to conditions (e.g., see Fig. 1). In both cases, the ultimate goal is to balance across conditions.