Important Considerations
By default when a project is created, the project will host only a single arm. Typically, a single arm is adequate for most project workflows. Arms can be used in the event that a study has groups of different participants, which follow unique workflows, however we discourage using Arms for this use-case and instead suggest the use of (FORM DISPLAY LOGIC) due to the below callouts:
Randomization: REDCaps Randomization functionality can only be configured for a single Arm. It is NOT possible to randomize participants using multiple arms.
Reporting: Reports will pull data from both arms, unless an Event Arm ‘filter’ is applied to your report
Data Exports: will include the ‘redcap_event_name’ field which indicates which arm the record data was exported from
When adding new records to the project, it’s critical the participant be added to the correct arm. Often users forget they have multiple arms causing error & confusion. Once a participant is added to a specific arm, there is no built-in REDCap functionality to move a participant to different arm. This can only be accomplished using manually data enter/export/import. Additionally, the system will not block you from having duplicate record IDs across arms, but does display a warning message in the event of Record ID duplication.
The Process
To use ‘Arms’ your project must first be enabled as a longitudinal project
If you project isn’t already longitudinal, this typically indicates you do not/should not utilize the arms functionality! More info: https://utahctsi.atlassian.net/servicedesk/customer/portal/3/article/2341765121?src=1897803665
Navigate to your ‘Project Setup’ page and click ‘Define My Events’
Here you will see the option to add an addition arm (shown below in red)
Title Arm & Save
Designate instrument to Arm events (just like you would in a single armed, longitudinal project)
Designate & Save
