có một kế hoạch ban đầu (tiến độ và thường chi phí và công sức), được sử dụng để tính toán phương sai. Về lý thuyết, chúng ta nói về lạnh cơ bản, sớm trong dự án. Nhưng tất cả chúng ta đều biết rằng một đường cơ sở đông lạnh như tuyết khả ố. | 220 CHANGE CONTROL AND SCOPE there is a baseline plan schedule and usually cost and effort which is used to calculate variances. In theory we talk about freezing the baseline early in the project. But we all know that a frozen baseline is like the abominable snowman. It is a myth and it melts under pressure. So the issue becomes What are valid changes to the baseline and how do we incorporate such changes into the database There are some reasonable and practical approaches which we share with you here. There is also an auxiliary benefit from addressing baseline management. It also provides a basis for controlling the demon of all projects scope creep. A Basic EVA Concept When we develop a project plan we identify the work to be performed activities and tasks which we then schedule and budget. Once we have negotiated a feasible plan one that balances the work objectives with schedule resource and cost considerations we establish that plan as the baseline. A basic premise of the earned value analysis protocol is that we establish such a project baseline and then evaluate progress against that target. The traditional EVA nomenclature uses this target the Budget at Completion BAC as an essential component of the base formula. The planned effort to date which we call the Budgeted Cost of Work Scheduled BCWS is calculated by multiplying the BAC by the planned percent complete. Sounds complicated It s really not. If you have identified a task and a cost budget for that task then you have the BAC. If you have scheduled that task then the system knows the planned percent complete at any point in time. When the system multiplies the budget by the planned C it has calculated the BCWS which is the planned accomplishment at a specific point in time. Your software will do all of this for you. All that you have to do is read the results of the calculations. Later when you have entered the task progress the system will use the actual C to calculate the Budgeted Cost of Work .
