Table 1.

Considerations for the choice of a restricted randomization procedure

Objective	Desired feature(s) of a randomization procedure
Mitigate potential for selection bias	A procedure should have high degree of randomness.
Mitigate potential for chronological bias.	A procedure should balance treatment assignments over time.
Valid and efficient treatment comparison	A procedure should have established statistical properties, provide strong control of false positive rate and yield unbiased, low variance estimates of the treatment difference. A procedure should preserve the unconditional allocation ratio (e.g. 1:1) at every allocation step and achieve approximately or exactly the target sample sizes per group.
Ease of implementation	Validated statistical software for implementing a randomization procedure must be in place.