The risk register is a dynamic document that must capture not only planned risk responses but also the actual outcomes of risks and the effectiveness of risk responses implemented. According to the PMBOK® Guide:

“The risk register should be updated with information on the results of risk responses, risk event outcomes, and actual effectiveness of the actions taken. This enables ongoing learning and continuous improvement in risk management.”

— PMBOK® Guide, 6th Edition, Section 11.7.3.2 (Project Document Updates: Risk Register)

This ensures that both the realized outcomes of risks and the success or failure of responses are tracked for future reference and lessons learned.