Dynamic allocation and minimisation

Dynamic allocation moves away from having a pre-specified randomisation list and the allocation of patients evolves as the trial proceeds. The method looks at the current balance, in terms of the mix of patients and a number of pre-specified factors, and allocates the next patient in an optimum way to help redress any imbalances that exist at that time. 

For example, suppose we require balance in terms of sex and age ( 65 versus 65) and part way through the trial we see a mix of patients as in Table 1.1. 

CHOI BASIC IDEAS IN CLINICAL TRIAL DESIGN 

Since the publication of ICH E9 there has been considerable debate about the validity of dynamic allocation, even with the random element. There is a school of thought which has some sympathy within regulatory circles that supports the view that the properties of standard statistical methodologies, notably p-values and confidence intervals, are not strictly valid when such allocation schemes are used. As a result regulators are very cautious  

CPMP (2003) Points to Consider on Adjustment for Baseline Covariates  

---