Define the minimization

Create a minimization design to balance the number and characteristics of subjects across treatment arms.

You can create a minimization design if the study's aim is to create better-balanced treatment groups. Minimization can be used in conjunction with restricted randomization. In case not all kit types are available during the study, the balance is calculated based on the remaining treatment arms during the study conduct period.

To maximize the potential of allocation methods specific to minimization, you can include a site, country, or region one at a time, as a location for the stratification factors. Additionally, you may also create custom groups within a stratum factor that is based on multiple-choice questions, if you want to balance out the options in fewer groups than the existing options.

Lastly, multiple minimization stratum factors can have the same weight.

Before you begin, make sure the following prerequisites are already set up in your study design:

• Treatment arms.

  For step-by-step instructions, see Define treatment arms.

• Appropriate questions in your forms, such as questions on age, race and ethnicity, or gender.

  For step-by-step instructions, see Question types and settings.

• Validation rules.

  For step-by-step instructions, see Set up a validation rule for a question.

To create a minimization design:

1. Access the Draft version of a study as described in Open a study's design.
2. 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.

   Field	Description
   Title	Enter the name of the minimization design, such as Minimization 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.
   Randomization	Select minimization to make sure subjects are evenly placed among treatment arms based on minimization stratum factors
   Re-Randomization	Planned for a future release.

6. On the Stratum page, on the right, click Select a Form and select a form.
7. Begin dragging and dropping the parameters to the Minimization Stratum Factors section.
8. For each stratum factor, in the Weight field, enter a number to define the weight (so the proportion) of each factor.
   • If you want to use the default groups for balancing subjects, you have to enter a whole number (from 0 to 99) in the Weight field for each stratum factor.
   • If you want to create custom groups for the stratum factors based on multiple-choice types of questions or range groups for age, click Create Custom Group and specify the details of the custom group. Then, define the Weight of each stratum factor.
9. Click Next.
10. On the Treatment Arms display, enter the ratio (a whole number, from 0 to 99) for assigning subjects to each treatment arm in the study.
11. On the Settings page, for the Restrict Randomization to Available Kit Types setting
    • 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.
    • Select No to enable a randomization failure to occur, though the site user can try to randomize the subject later.
12. Click Finish.

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