What is Subsidiary Management Plans?
The project management plan is a binder of subsidiary plans, one per discipline: scope, requirements, schedule, cost, quality, resource, communications, risk, procurement, and stakeholder engagement management plans. Each answers the same question for its domain: how will we plan, execute, and control this aspect? — rules and process, not the content itself.
The pattern to internalize once: the schedule management plan isn't the schedule; the risk management plan contains no risks. Plans-about-how versus documents-of-what — CAPM tests this boundary relentlessly.
Worked example
A new coordinator opens her project's cost management plan expecting numbers and finds rules instead: estimates at ±10% before baselining, EV measured monthly by control account, variances beyond 8% trigger written analysis, contingency drawn only via change request. The actual numbers live in the cost baseline. Once she sees the how/what split in one plan, she can navigate all ten.