Comprehensive and Detailed Before taking corrective actions like adding resources (B) or applying schedule compression techniques (D), the project manager should first understand the root cause of the delay. RCA helps identify whether the issue is due to skill gaps, workload, ambiguity, or other factors. This step ensures that the right mitigation strategy is implemented. Reference: * PMBOK Guide - Seventh Edition, Performance Domain: Planning, Section on Root Cause Analysis * PMBOK Guide - Risk and Schedule Management Concepts