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Stratification factors

In the studies that use permuted block randomization method, stratification, and multicentral randomization—meaning that the first stratification factor is a site to which the subject belongs—you need to specify all the stratification factors that the system will use to randomize subjects into treatment groups.

Stratification factors are the variables that are used to divide a group of subjects into subgroups according to certain criteria. An example of stratification schema is shown in the following figure.

Viewing stratified factor schema
Figure 1. Viewing stratified factor schema

In IWRS, you can set two types of stratified factors:

In this section:

A method of randomization that involves the preparation of a randomization list before initiating the randomization process for the study. Randomization of subjects is first performed into blocks according to preset stratification factors and then into arms according to specific ratios.

See also: dynamic randomization