Overview

The Randomization module manages treatment allocation and related setup for your study. Use this page to configure the blinding method, randomization algorithm, target event, sample size support, required pre-randomization data, and notification emails.

Configuration URL pattern: https://[instance]/home/study/[studyId]/apps/randomization

Before you begin

Before setting up Randomization:

• Make sure the study already exists and the Randomization app is installed.
• Create your Subject Group Class with treatment arms (e.g., Active Treatment + Placebo) before configuring the algorithm — the Randomization module reads arm codes from there.
• Complete your event design: the event used for randomization must exist before you can select it.
• Prepare any stratification fields if you plan to balance allocations by subject characteristics.

Step 1: Open the Randomization app

1. Open the target study.
2. Go to Randomization (in the Installed Apps sidebar or from the study home).
3. Review the configuration sections on the main page.

On the main page you can access these setup areas:

• Blinding Method and Algorithm settings
• Algorithm-specific settings (e.g., Stratified Permuted Block Design)
• Select event to Randomize
• Sample Size
• Additional data before Randomization
• Email Notification

Step 2: Choose blinding method and randomization algorithm

In Blinding Method and Algorithm settings, select Edit.

Blinding methods:

Option	Description
Single Blind	CRC and study staff know the subject group.
Double Blind	Only Sponsor and Study Admin know the subject group.

Randomization algorithms:

Algorithm	Best for
Permuted Block Design	Simple balanced allocation with fixed block sizes
Stratified Permuted Block Design	Balanced allocation with stratification by site or other factors (most common for multi-site RCTs)
Big Stick Design	Adaptive balancing without fixed blocks
Minimization Design	Covariate-adaptive minimization across multiple factors

Select your options, then choose Save.

Step 3: Configure algorithm-specific settings

After saving the algorithm, the algorithm-specific settings section appears on the main page. Select Edit.

Stratified Permuted Block Design (example)

This is the most commonly used algorithm for double-blind, multi-site Phase III trials.

Setting	Description
Study Groups	Add one row per treatment arm: Label, Code, Weight, Description
Block size	Number of subjects per block (e.g., 4 = balanced in groups of 4)
Generate randomization list	Choose Real-time (assign at subject randomization) or pre-generate
Level of Stratification	By Site (balance within each site) or By Study (balance across whole study)

Example study groups for a 1:1 RCT:

Label	Code	Weight	Description
CardioRelief CRF-101	TRT	1	Active treatment, 50mg once daily
Placebo	PBO	1	Matching placebo once daily

Select Submit to save.

Tip: The Code values here must match exactly the codes used in your Subject Group Class (Step 3 in the study build flow).

Stratification Factors (Stratified Permuted Block Design only)

When using Stratified Permuted Block Design, a Stratification Factors Information table appears below the algorithm settings. Add one row per stratification variable.

Select Edit on the algorithm settings card, then choose Add Stratification in the Stratification Factors section.

For each stratification factor, fill in:

Field	Description
Stratification From	Source of the stratification value — currently supports A CRF (a Radio/Checkbox field in a study form)
CRF / Default Version	The CRF and version containing the stratification field (e.g., CRF 4 - NYHA Classification - V.1.0)
Visit / Event	The study event at which the field is collected (e.g., Screening)
Field	The specific Radio/Checkbox field within the CRF (e.g., NYHA Class)
Options	Auto-populated from the field's answer choices — all options are included and cannot be manually edited

Select Submit to save each stratification factor.

Note: Only fields of type Radio or Checkbox can be used as stratification variables. Numeric and free-text fields are not supported. If the field you need is not in the list, verify its type in the Form Builder.

Example stratification factors for a Phase III cardiac trial:

Stratification From	Visit	Field	Options
CRF 4 - NYHA Classification - V.1.0	Screening	NYHA Class	Class I, Class II, Class III, Class IV
CRF 6 - Echocardiography (LVEF) - V.1.0	Screening	LVEF Method	Simpson's Biplane, Teichholz, Visual Estimate, 3D Echo

Best practice: Keep stratification factors to 2–3 variables. Each additional variable multiplies the number of strata, which can lead to many small strata with few subjects and poor balance if the study is underpowered.

Step 4: Select the event used for randomization

In Select event to Randomize, choose Edit.

Setting	Description
Select Event	The study event where randomization takes place (e.g., "Randomization / Baseline")
Override CRF name	Optional — rename the auto-generated randomization form
Position of randomization form	Where the form is inserted within the event (e.g., "At first position")

Select Submit to save.

Note: Only one event can be selected. A randomization form is automatically added to the end of the selected event.

Step 5: Calculate sample size (optional)

In Sample Size, choose Calculate to open the power calculator.

Enter any 3 of the 4 parameters and the tool will calculate the remaining value:

• Sample size
• Effect size
• Power
• Significance level

Step 6: Define additional data required before randomization

In Additional data before Randomization, choose Edit.

The dialog includes:

• Options — The answer format shown to users (default: Yes / No).
• Inclusion questions — Add one row per criterion. Subjects must answer Yes to all inclusion questions to proceed.
• Exclusion questions — Add one row per criterion. Subjects must answer No to all exclusion questions to proceed.
• Open questions — Free-entry questions that do not gate randomization.

Example: Phase III cardiac trial

Inclusion questions:

1. NYHA Class II or III confirmed
2. Age 18–80
3. LVEF ≤ 40% on screening echo
4. No prior CRF-101 exposure

Exclusion questions:

1. eGFR < 30 mL/min/1.73m²
2. Active malignancy
3. Pregnancy or breastfeeding

Select Submit to save.

Step 7: Configure email notification

In Email Notification, choose Edit.

Setting	Description
Role-based recipients	Check each role that should receive a notification: Study Administrator, Investigator, Site Monitor, etc.
Also send email to	Additional email addresses (up to 30), separated by colons
Email Subject	The notification subject line
Email Content	Rich text message body — use View all Variables to insert template variables

Select Submit to save.

Verify the setup

After completing all steps, review the values shown on the Randomization main page:

• Blinding method and algorithm match your protocol
• Treatment arms show correct labels, codes, and weights
• Correct event is selected
• Block size and stratification level are correct
• Pre-randomization questions are complete
• Notification recipients and content are correct

Best Practices

• Create the Subject Group Class before configuring Randomization — the arm codes must match.
• Use Stratified Permuted Block Design with By Site stratification for multi-site RCTs to ensure balanced allocation at each site.
• Use Block size 4 for 1:1 allocation (2 per arm per block) — provides good balance while maintaining allocation concealment.
• Set Real-time list generation for most studies (avoids pre-generating unused allocations).
• Test the full subject randomization flow in a non-production environment before Go Live.
• Document any changes to the randomization method for audit and regulatory compliance purposes.