Overview

The Randomization module (also known as RTSM / IWRS) manages treatment group allocation and blinding for clinical trial subjects. It ensures subjects are assigned to treatment arms according to the study protocol, with full audit trail and double-blind capability.

Key capabilities:

• Multiple randomization algorithms — Permuted Block, Stratified Permuted Block, Big Stick, and Minimization Design
• Double-blind support — treatment assignments are hidden from site staff; only Sponsor and Study Admin can view the subject group
• Site-stratified allocation — balance treatment arms across multiple sites using stratification factors
• Pre-randomization eligibility checks — enforce inclusion and exclusion criteria before a subject can be randomized
• Automated email notifications — notify designated roles when a subject is randomized
• Real-time list generation — allocation is determined at randomization time, eliminating pre-generated list management

Direct URL pattern:

https://[instance]/home/study/[studyId]/apps/randomization

Replace [instance] with your environment host (for example, test-2025.clinicaldatas.net) and [studyId] with the study identifier.

Who uses this screen

The Randomization configuration screen is used by the Study Administrator to set up and manage the randomization algorithm, blinding method, eligibility questions, and notifications. Site staff (Investigators, CRCs) interact with randomization through the subject data capture workflow at the designated randomization event — they do not access this configuration page directly.

If you cannot open the Randomization app or the Edit buttons are greyed out, verify that the study is in Design status. Configuration changes are not permitted while the study is in Production.

Opening Randomization

1. Sign in to your ClinicalDataS instance (for example https://test-2025.clinicaldatas.net).
2. Open the study you work on.
3. In the left sidebar under Installed Apps, select Randomization.

The Randomization configuration page opens, showing all setup sections.

Note: If the study is in Production status, a banner appears: "To set it up, please change the status of Study to Design." The Edit buttons are disabled until the study is switched back to Design.

Main screen layout (observed)

The Randomization page is organized into configuration cards, each covering one aspect of the setup. The cards appear in this order:

Card	Description
Blinding Method and Algorithm settings	Configure all randomization settings including blinding method and algorithm type
[Algorithm-specific settings]	Appears after saving an algorithm — the card title matches the selected algorithm (e.g., Stratified Permuted Block Design)
Select event to Randomize	Select which study event triggers randomization
Sample Size	Optional power calculator for determining required enrollment numbers
Additional data before Randomization	Define inclusion, exclusion, and open-ended questions subjects must answer before being randomized
Email Notification	Configure who receives email alerts when a subject is randomized

Each card has an Edit button (pencil icon) in the top-right corner. In Production status, Edit buttons are disabled.

Blinding Method and Algorithm settings

Select Edit to open the dialog. Choose the Blinding Method and Randomization Algorithm.

Blinding Method:

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

Randomization Algorithm:

Algorithm	Description
Permuted Block Design	Create blocks with treatment assignments shuffled according to the predefined allocation ratio
Stratified Permuted Block Design	Same as Permuted Block but separated by strata. You have to define stratification variables in setting below.
Big Stick Design	Allows imbalance in a predefined MTI; if exceeded, assigns to the group with lower count.
Minimization Design	Assigns the patient to a group that minimizes imbalance across covariates. Balancing updates in real-time.

Select Save to confirm. The algorithm-specific settings card will appear below.

Algorithm-specific settings

After saving an algorithm, a new card appears for its specific settings. The card title matches the selected algorithm name (for example, Stratified Permuted Block Design).

Common settings across algorithms:

• Study group — A table with columns: Label, Code, Weight, Description. Add one row per treatment arm.
• Block size — Number of subjects per block.
• Define different ways to generate randomization list — Generate at real-time when a new subject is randomized, or pre-generate.
• Level of stratification (Stratified Permuted Block only) — By Site or By Study.
• Stratification Factors Information (Stratified Permuted Block only) — Table linking CRF fields to stratification variables.

See Configuration for full algorithm-specific setup details.

Select event to Randomize

Select Edit to open the dialog.

Only 1 event can be selected. There will be a randomization form at the end of the selected Event.

Field	Description
Select Event	Dropdown to choose the study event where randomization takes place. Use Reload to refresh the event list. A Manage Events link is available to navigate to event management.
Randomization form name	Optional name for the auto-generated randomization form added to the selected event.
Position of randomization form	Where the form is inserted within the event (for example, "At first position").

Select Submit to save.

Sample Size

Select Calculate to open the Calculate Simple Power dialog.

Enter any 3 of 4 following parameters to calculate the rest one.

Parameter	Description
Sample size	Number of participants in each condition
Effect size	Cohen's d — standardized mean difference between groups
Power	Probability of detecting a true effect (default: 0.8)
Significance level	Probability of Type I error (default: 0.05)

Enter three of the four values and select Calculate to compute the remaining parameter.

Additional data before Randomization

Select Edit to open the dialog.

Notes: Inclusion is required to answer with Yes. Exclusion is required to answer with No. Open is other types of questions.

Setting	Description
Options	Default answer labels — defaults to Yes / No. Enable Custom options to use alternative terms (for example, "Agree / Disagree" or localized labels for a different study language).
Inclusion question tab	Add criteria that subjects must answer Yes to in order to proceed with randomization. Each row has a Label (required) and optional Description.
Exclusion question tab	Add criteria that subjects must answer No to in order to proceed with randomization.
Open question tab	Free-entry questions that do not gate randomization.

Select Submit to save.

Email Notification

Select Edit to open the dialog.

Configure email notification when a subject is randomized.

Setting	Description
Send email notification to following recipients	Check each role that should receive a notification: Study Administrator, Study Monitor, Study Sponsor, Investigator, Site Monitor, Clinical Research Coordinator
Also send email to following recipients	Additional individual email addresses (up to 30 recipients)

Select Submit to save.

Workspace tabs

After opening Randomization from the study workspace, the top navigation bar exposes all functional areas:

Dashboard · Subjects · Requests · Randomization Codes · Tools · Export · All Tasks

Dashboard

The Dashboard tab gives a high-level view of enrollment and randomization progress across sites and treatment arms.

Subjects

The Subjects tab is the main worklist. It lists every subject that has been randomized or is pending randomization, with columns for Subject ID, Randomization Code, Site name, Randomized On, Randomized By, Study Group, and Status.

Use Search to filter by subject or site. Use Export as to download the list.

Top counters show:

• Total — all subjects in scope
• Randomized — successfully assigned to a treatment arm
• Ready — passed eligibility checks, awaiting randomization
• Failed — failed one or more eligibility checks

Requests

The Requests tab tracks pending and completed randomization requests — useful when requests require approval or are queued for processing.

Randomization Codes

The Randomization Codes tab shows the pre-generated or real-time allocation list. Each row corresponds to a randomization code, its assigned treatment arm, and the subject it was allocated to (if any).

Tools

The Tools menu provides utility functions such as:

• Simple Power — sample size / power calculator
• Futility Analysis — interim stopping rules
• AE Prediction — adverse event modeling tools

Export

The Export tab lets you download randomization data in standard formats for reporting and audit purposes.

All Tasks

The All Tasks menu aggregates pending actions across the Randomization module, including tasks assigned to the current user or their role.

Typical workflow

1. Install the Randomization app on the study (study must be in Design status).
2. Before configuring Randomization, create the Subject Group Class with treatment arm codes in study setup — the algorithm reads arm codes from there.
3. Open Randomization and configure each card in order:
   • Blinding Method and Algorithm settings — choose blinding and algorithm, then Save.
   • Algorithm settings — configure study groups, block size, and stratification factors.
   • Select event to Randomize — choose the event and form name.
   • Sample Size — optional; use the power calculator if needed.
   • Additional data before Randomization — define eligibility questions.
   • Email Notification — select recipients and customize the message.
4. Go Live — switch the study to Production. Subjects can then be randomized at the designated event visit by site staff.

Algorithms

Algorithm	Description
Permuted Block Design	Create blocks with treatment assignments shuffled according to the predefined allocation ratio
Stratified Permuted Block Design	Same as Permuted Block but separated by strata. Define stratification variables in algorithm settings.
Big Stick Design	Allows imbalance in a predefined MTI; if exceeded, assigns to the group with lower count.
Minimization Design	Assigns the patient to a group that minimizes imbalance across covariates. Balancing updates in real-time.

Related topics

• Configuration — Step-by-step setup guide covering algorithm options, stratification, additional pre-randomization data, and email notifications
• Install an App — How to install or open any CDS module on a study