The blue book is a gem for Software Project Managers. For many years after reading the Bible of Software Engineering I did not find a concise explanation that would give me hope on the possible existence after all of a Silver Bullet for Project Management but I have found in David J. Anderson's book a great must-read-first for those still looking for it.
Prioritization and estimation are important and at the same wasteful activities. At the core of a good decision is a proper triage system.
Every software issue should have a class of service (COS) to make sure its high level priority is understood and that the proper SLA is applied.
IMO they are not to be confused with severity which is an important classification for Standard and Intangible COS or priority number which allows to further qualify tickets within severity.
COS and teams are orthogonal. Let us analyze an example to clarify how technology support tickets can have any COS.
Technology tickets are *not* always intangible. Technology debt can be a huge problem if the tickets are not properly prioritized. As technology leaders we need to make sure we explain these important concepts to the stakeholders. Classes of Services are completely orthogonal to teams.