Set up (double) blinded randomization


  • It is possible to set up blinded randomization in Castor by assigning appropriate rights to users
  • There are two separate user rights that are linked to randomization: ‘Randomize’ (Rand.) and ‘View Randomization’ (View rand.). 
  • Each of these rights can be assigned to different users and institutes.
  • With the Randomize right, a user can randomize patients (records).
  • This is done via the Randomization tab within a record. 
  • The View Randomization right is necessary to see to which group a record has been allocated. 
  • The user with Randomize rights only will see the date of randomization and by whom the randomization was performed, but the allocation and randomization number will remain hidden.
  • This means that users who need to be blinded to the group allocation should not have View Randomization rights. 
  • To unblind the randomization, assign the View Randomization right to the user who needs unblinding at the end of the study. 
  • In my study, the user will not be able to see the randomization allocation for the Test Institute.
  • This is captured in the audit trail.
  • Make sure that the forms are also built to preserve the blinding. 
  • There should be no questions that are dependent on the randomization group, nor should the outcome of randomization be used in a calculation or summary field. 
  • The randomization field in your study will indicate 'Hidden' for users without View Randomization rights.

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