Define the randomization

Create a randomization design either to specify randomization details or to start an open-label period, even if the open-label period doesn't have a randomization event.

Before you begin, consider the following:

• You must first define treatment arms. For step-by-step instructions, see Define treatment arms.
• If you need to edit a read-only field after assigning a randomization design to a visit, remove the randomization design from the visit. You can edit the description and the settings on the last page at any time.

Note:

The page where you specify a treatment ratio (named either Treatment Arms or Cohorts & Treatment Arms, depending on whether the study has cohorts) doesn't appear if you selected Yes for Re-Randomization on the first page. Instead of mapping subject to treatment arms here, you'll map subjects from their current treatment arms to their new treatment arms when you drag this randomization design to a visit.

Want to see how to perform this task? Watch the video below.

Task 1   Specify how you will randomize subjects

1. Access the Draft version of a study as described in Open a study's design.
2. Along the top, click Study Supplies.
3. Make sure the Randomizations tab is selected.
4. Click Create Randomization.
5. Fill in the rest of the fields on the page and click Next.

   Note:

   Make sure you've defined treatment arms for each cohort group before you define randomization. If cohort groups don't have at least one treatment arm defined for each cohort group, you won't be able to assign demographic cohort randomization to visits.

   Field	Description
   Title	Enter the name of the randomization design, such as Simple randomization design 1:1.
   Description	Provide additional information that doesn't fit in the title.
   Type	If blinded users should never see any of the titles of the treatment arms used in the randomization design, choose Blinded. If blinded users should always see all titles of the treatment arms used in the randomization design, choose Unblinded.
   Cohort	Choose one of the following: None to create a study without cohorts. Adaptive to create cohorts that allow you to open treatment arms in a gradual manner so that you can better measure safety and efficacy as the study progresses. Demography to create population groups according to demographic criteria, such as age. You can set limits on each group and can open and close demography cohorts based on the results obtained during the study conduct period. You can also increase and decrease the number of subjects in each population group as needed.
   Randomization	Specify how subjects are randomized: Use dynamic randomization (recommended) to use the numbers in the list more efficiently. This can help reduce having large sections of unassigned numbers. To use stratified randomization (not available for cohort studies), select a randomization type with Stratification in its name. If you want to stratify subjects by demographic criteria and want to place limits on each population group or have the ability to stop and start enrollment with just a few clicks, you should choose Demography from the Cohort drop-down.
   Re-Randomization	Appears only when you create a second or later randomization design and you select a randomization algorithm. Select Yes if you'll use the randomization design for the second or later randomization event in the study.
   Treatment Arms	Appears when you select Yes for Re-Randomization and when you select a non-stratified randomization algorithm. Select Randomized if all subjects are randomized into new treatment arms according to a treatment ratio that you specify in the randomization design. Select Mapped to map subjects to new treatment arms (or to specify that they should stay in their current treatment arms). Note: If subjects in one treatment arm are mapped to multiple arms, randomization determines the subjects' new treatment arms.

Task 2   Create stratum groups (For any stratified randomization with None selected for Cohorts)

1. On the Stratum page, from the Select a Form drop-down on the left, select a form that contains a question that you are using to stratify subjects.

   The questions that can be used to stratify subjects appear. Only the following questions can be used to stratify subjects:

   • A required Number or Age question with a Range validation rule for which Include Value in Range is selected.
   • A required Drop-down question with a Select Exactly validation rule that allows 1 selection.
   • A required question with radio buttons.
2. Drag a question to Stratum Group 1, on the right.
3. Finish configuring the stratum group, either by dragging questions from the selected form, or by selecting a different form from the drop-down and dragging questions.
4. Define the details of the stratum group:
   • For number questions, specify the range for subjects in each group.
   • For drop-down questions or questions with radio buttons, select one or more options for each stratum group.
5. In the upper-right, click the plus sign, and define as many stratum groups as you need. When defining the details of the group, make sure that:
   • All values in the range of number and age questions are captured in the stratum groups.
   • Number ranges don't overlap.
   • All options on a drop-down question or a question with radio buttons are captured in the stratum groups.
6. Click Next.

Task 3   Create cohort groups (for Demography selected for Cohorts)

1. On the Cohorts page, from the Select a Form drop-down on the left, select a form that contains a question that you are using to create population groups.

   The questions that can be used to create population groups appear. Only the following questions can be used to create population groups:

   • A required Number or Age question with a Range validation rule for which Include Value in Range is selected.
   • A required Drop-down question with a Select Exactly validation rule that allows 1 selection.
   • A required question with radio buttons.
2. Drag a question to the area below Enter Cohort Name, on the right.
3. Finish choosing questions for the stratum group, either by dragging more questions from the selected form, or by selecting a different form from the drop-down and dragging questions.
4. Define the details of the cohort group:
   • For number questions, specify the range for subjects in each group.
   • For drop-down questions or questions with radio buttons, select one or more options for each cohort group.
5. In the upper-right, click the plus sign, and define as many cohort groups as you need. When defining the details of the group, make sure that:
   • All values in the range of number and age questions are captured in the cohort groups.
   • Number ranges don't overlap.
   • All options on a drop-down question or a question with radio buttons are captured in the cohort groups.
6. Click Next.

Task 4   Specify the treatment ratio for treatment arms, stratum groups, or cohorts

1. (Only for a study with adaptive cohorts) On the Cohorts & Treatment Arms page, click the plus sign in the upper-right corner () to create all the cohorts in the study.

   Tip: The number on the Cohorts column indicates the number of cohorts you create.

2. Enter a whole number (from 0 to 99) for each stratum group, treatment arm, or cohort in the study.

   The numbers determine the treatment ratio, such as 2:2:1:1, for each treatment arm, stratum group, or cohort. If you don't enter a number, subjects aren't randomized into the treatment arm, stratum group, or cohort.

3. Click either Finish (for a study with cohorts) or Next (for a study without cohorts).

Task 5   Specify additional randomization details

Note:

This page doesn't appear if you're randomizing into cohorts.

1. On the Settings page, fill in the fields and click Finish.

   To view a tip for completing the field, choose an option.

   Setting	Description
   Assign New Randomization Numbers to All Subjects	This setting appears when you select Yes for Re-Randomization on the first page). Select Yes if subjects should receive new randomization numbers after they are randomized as part of this randomization design. Select No if subjects should not receive new randomization numbers after they are randomized. Note: For both selections, you are required to upload a randomization list that is associated with this re-randomization design. Even though you decide that subjects should not receive new randomization numbers, a randomization list is still required to preserve the blind in a blinded re-randomization.
   Restrict Randomization to Available Kit Types	Select Yes if you want randomization to skip the randomization number for an out-of-stock kit and assign the randomization number for the next available kit. If you select No, a randomization failure occurs, though the site user can try to randomize the subject later.
   Assign Skipped Randomization Numbers	Select Yes if, when a randomization number is skipped because its kit is not in stock, the skipped randomization number is assigned to a subject who enrolls after the out-of-stock kit is available again. The analysis of randomization is sometimes easier with this option. Select No if skipped randomization numbers are never assigned.
   Allow Randomization to Occur Outside Visit Window	Select Yes if you want to let a site user start and complete a randomization visit (without dispensation) outside of the specified visit window for that randomization visit. Select No if you want to restrict a site user to only randomize a subject if they start the randomization visit (without dispensation) during the specified visit window.

2. If you created a region-blocked randomization design, don't forget to Add a region.

Next up, you must add your randomization design to a visit. For step-by-step instructions, see Add randomization to a visit.