General

To use Study Randomizer:

  • Register for an account using the "Register" dropdown in the bar at the top of this page.
  • Follow the instructions in your email to finish creating an account.
  • Once your account is created, click "Dashboard". Your Dashboard gives you an overview of all the studies available to you.
  • Click "Create new organization". Enter your organization name, and click "Create". You should see the new organization appear on the screen.
  • Click "Create new study". Fill out the form with details about your study, and click "Save". If you are ready to enroll participants right away, ensure that the "Active" box is checked.
  • Your study is now ready to begin! When you are ready to enroll participants, go back to your Dashboard and click "Enroll participant".

You may wish to add additional users to your group (e.g. a study coordinator). See "How do I add people to a study?" for more information.

Once your study has been created, any user in your organization with the "Enroll participants in studies" permission can enroll participants by clicking on the "Enroll participant" button, visible from either the Dashboard or from your organization's page.

If the study settings call for stratification or information collection, the user will be prompted to fill out a short form.

After completing the form, the arm that the participant has been randomized into will be displayed. At this point, the participant has been enrolled!

Users with the "Edit studies" privilege can view enrollment history by clicking on the study name on either the Dashboard or from your organization's page.

If at least one participant has been enrolled, the "Enrollment" table will be visible, which includes the unique ID, the randomized arm, any strata or information collection results gathered during enrollment, and a timestamp showing when the participant was enrolled.

Study Randomizer is developed and maintained by Jason Wright.

Studies

The "Active" box enables or disables enrollment in the study. Enrollment is disabled unless the "Active" box is checked.

You can use the "Active" box to pause enrollment in a study even after it's already started.

A study's options are locked once at least participant has been enrolled in a study. We don't want study options to get changed without restarting a study as the randomization may no longer be valid!

If you want to change study options at this point, you'll need to restart the study.

Enrollment may not be available for any of three reasons:

  1. The study isn't active.
  2. The user doesn't have both of the "View studies" and "Enroll participants in studies" permissions for your organization.
  3. The study is complete, i.e. all participants have already been enrolled.

Ensure that the study is active and that the user attempting to enroll participants has the right permissions.

Permuted block randomization takes your study group and divides the participants into blocks of equal size. The arms of the study are balanced within each block, in a random order that is generated upon the start of the study. If the study size isn't evenly divisible by the block size, the remainder of the participants are put into a smaller block.

During enrollment, the blocks are filled sequentially with new patients. The randomization occurs at the start of the study, so the order is pre-determined.

For example:

  • A study with size 50 and two arms ("control" and "treatment") uses permuted block randomization with block size of 8.
  • 6 blocks of size 8 are created. The remainder of the participants are put into a block of size 2.
  • The first 8 participants are randomized using the order defined in the first block. It is guaranteed that the randomization within the block is balanced, i.e. 4 of them will be assigned to the "control" arm and 4 will be assigned to the "treatment" arm.
  • The last 2 participants are randomized using the "remainder" block.
  • If the size of any block is an odd number, the randomization will achieve as close to an even balance as possible. For example, if the study had a block size of 7, each block would have either 4 "control" participants and 3 "treatment" participants, or 3 "control" participants and 4 "treatment" participants.

Matts JP, Lachin JM. Properties of permuted-block randomization in clinical trials. Controlled clinical trials. 1988; 9(4):327-44. [pubmed]

Urn randomization is an adaptive randomization scheme in which the choice of arm for each participant is weighted based on prior randomizations.

For example:

  • A study with two arms ("A" and "B") uses urn randomization.
  • "A" and "B" are both placed into an urn. The first participant is randomized by choosing an arm from the urn.
  • If "A" is chosen, "A" is returned into the urn and an additional instance of "B" is added.
  • The urn now contains ["A", "B", "B"] and the next participant is randomized by choosing an arm from the urn.

If the study has more than two arms, e.g. "A", "B", and "C", each of the arms that isn't selected for each randomization gets added to the urn. For example, if the urn starts as ["A", "B", "C"] and the first randomization is "B", the urn for the next randomization would be ["A", "B", "C", "A", "C"].

Wei LJ, Lachin JM. Properties of the urn randomization in clinical trials. Controlled clinical trials. 1988; 9(4):345-64. [pubmed]

Organizations

An organization represents a group of users and a group of studies.

All users in an organization have the same level of permission for all of the studies within the organization. (If you want some users to have permissions for only some studies, you'll need to create a separate organization!)

A user can be part of multiple organizations, but a study can belong to one and only one organization.

To add users to an organization, you must have the "Manage organization" permission. If so:

  • Click the "Dashboard" button.
  • Click the name of the organization to which you want to add someone.
  • Click the "Users" tab.
  • Click "Add user". Enter the person's name and email address.
  • You should see a row created for that user appear. If the user doesn't yet exist in the system, you'll see a (pending invitation) indicator until that user opens their invitation email and sets up their account.

To grant permissions to users to an organization, you must have the "Manage organization" permission. If so:

  • Click the "Dashboard" button.
  • Click the name of the organization to which you want to add someone.
  • Click the "Users" tab.
  • Check or uncheck the boxes corresponding to the permission you want to grant for the appropriate user.

The permissions available are:

  • View studies: This user can see the name, ID, method, and current enrollment count of studies in your organization.
  • Edit studies: This user can create new studies, edit study options, delete studies, and view enrollment history of studies in your organization.
  • Enroll participants in studies: This user can click the "Enroll participant" button and enter participant information for studies in your organization.
  • Manage organization: This user can add or remove users, change permissions for users in the organization, rename the organization, and delete the organization.

Security

Yes. All data is stored in an encrypted, protected database and backed up every day. All passwords are hashed and salted, ensuring that any attacker would not have access to raw passwords. All transactions are secured using HTTPS.

Yes. All interactions with the system are logged, including the authenticated user, the IP address, a timestamp, and the action performed. This information can be provided in the form of an audit log upon request.