I’m going to start with a basic assertion: to be effective and successful in their job, Project Managers need good information and the right tools. These two things are an absolute must. A bit more specifically: project managers first need current, accurate and complete project data; then secondly, they need the right tools to analyze, and report on that data. This is especially true when managing large construction projects, where there are so many moving parts, changes, documents, contractors, costs, schedules, etc. to stay on top of. There are other things they need of course, but without these two key things, construction project managers are left feeling around in a dark room, desperately hoping to find a light switch.
A must-read article on the effects of change in construction projects by Arthur O’Leary called Coping with Changes during Construction takes a very savvy look at both the reasons changes happen, along with strategies around managing the risk. While O'Leary's focus is on construction projects, this advice and rules are equally valid for projects in any industry that have complexities such as: many moving parts, suppliers, subcontractors, customers, complex WBS, multiple resource types, etc.