A project baseline is the original and approved project plan and depicts all key information and constraints. It includes, but is not limited to, scope baseline, cost baseline and schedule baseline. More simply, a project baseline is where you store all the scheduled values that were agreed upon during the project planning process and serves as a reference point. It allows the project team to measure their performance against the expectations and requirements that were set. Having a steadfast baseline is also important for assessing earned value as well as for improving the accuracy of future estimations.
It is also helpful in measuring the project’s progress and serves as a control instrument. Changes to the baseline during the process of the project might be necessary because of unforeseen events for example. However, constant change to the original plan could be an indicator of ineffective planning and communication in the early phases of the project.