Add permuted block randomization scheme

In IWRS, you can select the randomization method—permuted block or dynamic—per cohort. If you select to use the permuted block (PB) randomization method for the cohort, the first configurational step is to add the randomization scheme.

A randomization scheme is a plan according to which subjects enrolled in a study are randomized and receive their treatment. Thus, by adding a new scheme, you ensure that the required subjects are randomly assigned to arms.

To add a new permuted block randomization scheme to a cohort

In the IWRS application header, select the TREATMENT DESIGN tab.
On the page that opens, in the left pane, select the Period subtab.
In the Period List table that appears, locate the period of your interest. Then in the Period Name column, select the value to open the period configurator.

Figure 1. Selecting period to configure
In the period configurator, drill down the explorer tree and select Randomization List.
On the Randomization List page that opens, from the workspace toolbar, select New Item .

Figure 2. Selecting to add new randomization scheme

In the Add dialog that appears, start configuring your scheme by setting the preferences as described in the following table.

Figure 3. Adding new randomization scheme

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In the following table, mandatory elements are marked with an asterisk (*).

Element	Details
Randomization Name*	Enter a unique name of the randomization scheme you create.
Type*	Select one of the following randomization scheme types: System Generate Select this option if the randomization scheme is to be configured via entering all the needed configuration parameters from scratch directly in the IWRS system. Manual Upload Select this option if you want to configure the randomization scheme by uploading a configuration file from your computer and then mapping the fields in the file to the fields available in the IWRS system.
Method*	Select the method of your randomization scheme: Block This randomization method involves dividing participants into blocks or groups, with each block containing a predetermined number of participants. The treatment allocation is randomized within each block. Stratified This randomization method is only available for the manual upload type of configuration and it treats the whole randomization list as a single block to which the subjects are assigned based on meeting set stratification parameters, such as age, gender, disease severity, or other. With this method, the system assigns the randomization numbers to subjects within a single block. Block Stratified This randomization method is a mix of block and stratified methods. The subjects are divided into blocks incorporating an additional stratification factors—dividing participants into subgroups based on certain criteria such as age, gender, disease severity, or other. The system assigns randomization numbers within multiple blocks. In IWRS, for this method, you also need to select the stratification strategy. Complete This randomization method is the simplest and most basic and involves a random allocation of participants to treatment groups without any specific blocking or stratification. Each participant has an equal chance of being assigned to any treatment group disregarding their age, gender, disease severity, or other.
Use predefined strata	Set the parameter as follows: Turn on to enable predefined strata If enabled, the stratification data must be specified in the file uploaded for randomization scheme configuration. For this configuration, once the file is uploaded, the system checks if the subjects satisfy the predefined stratification parameters and assigns them with randomization numbers accordingly. Turn off to disable predefined strata If disabled, the file uploaded for randomization scheme configuration does not have the stratification data and you need to set it up manually in IWRS. `This selection is only available for the block-stratified method.`
Stratified Strategy*	Select the stratification strategy for your randomization. The values can be the following: Hierarchical Select this strategy if you need to arrange your stratification factors into hierarchical levels. For instance, the first level of stratification is by age, and the subjects are divided into two groups of 1-45 and 46-80 years old. The second level is by sex, and the subjects of each age group are divided into two groups—male and female. Then, each of the resulting four groups—1-45 male, 1-45 female, 46-80 male, and 46-80 female—are randomized into the respective arms of your study. Parallel Select this strategy if you want to consider your stratification factors as parallel equipollent values. For instance, one stratification factor is age, and another is sex. The subjects are divided into two groups by age—1-45 and 46-80 years old—and into two groups by sex—male and female. These stratified groups are not interconnected in any way. If the randomization ratio is satisfied by one of the stratification factors (for instance, by age), the subjects are randomized within these stratified groups regardless of the other ones (which, in our case, are stratified by sex). `This selection is only available for the following setups:` `For the system-generated type` `For the manual upload type with the block-stratified method and the predefined strata toggle turned off`
Stratified by Sites	Turn the toggle on so that the site is automatically used as the stratification factor.
SAVE	Select to add your randomization scheme.
CANCEL	Select to stop creating a randomization scheme, close the dialog, and return to the randomization scheme list of the Period configurator. In such a case, no changes are saved.

Once saved, the new randomization scheme is added. You can proceed with configuration of the randomization scheme.

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Add permuted block randomization scheme

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