The function of Root Cause Analysis (RCA) is to allow the users managing defects to see if there is an underlying change (SAP transport) related to the defect. Testimony leverages ActiveControl (A change and release product also built by Basis Technologies) to enable Testimony to look inside the transport to determine the underlying objects changed as a result of the release. These changed objects are checked to see if any defects have been raised for the transaction code, batch job, RFC or web service etc. an underlying change found it linked to the defect and the Root Cause Analysis flag is raised against that defect. Also note that RCA is designed to be run once the execution of the playback is completed, if utilising double playback this will be after the second run where you are testing your release.
To ensure the correct setup and running of Root Cause Analysis (RCA) please check the following steps.