Which phase of problem management includes the regular re-assessment of the effectiveness of workarounds?

Error control also regularly re-assesses the status of known errors that have not been resolved, taking account of the overall impact on customers and/or service availability, and the cost of permanent resolutions, and effectiveness of workarounds

https://www.bmc.com/blogs/itil-problem-management/#:~:text=Error%20control%20also%20regularly%20re,resolutions%2C%20and%20effectiveness%20of%20workarounds.