Linking Budget and Schedule – it’s a Challenging Task
One of the first principles of project controls is that the project budget has to be time-phased over the duration of the project. Here’s why: It’s not enough to simply know the total budget for a project – it’s critical to also know when that budget is planned to be spent. In other words, each quantity of material, labor hour or subcontractor service that’s planned for the project, is planned to occur at a particular time on the project. Some of these budget items happen over a time-span – like a service – and some happen at a point-in-time – like the delivery of some material. Together, all of these budget elements result in a budget timeline. That timeline is typically represented by a curve that plays-out over the life of the project. See the chart to the right. Click to Enlarge. S-Curve chart showing Budget over timeline along with Actuals, Earned Value and Estimate to Complete. There is more than one way to time-phase a budget of course. Nevertheless, what project controllers most often do to put their budget on a timeline, is establish a healthy connection between the project budget and project schedule. In theory, this should be a fairly straightforward exercise since both budget and schedule have a work breakdown structure (WBS) in common. As you’ve probably guessed however, theory is just theory and in reality it’s not that simple. Schedulers have a very distinct view of a project’s WBS as compared to estimators or cost engineers. Schedulers view the project from the perspective of activities, duration, milestones, dependencies and critical path. Their version of a WBS includes things like milestone tasks, progressing tasks and events. Things that