A Project Schedule consists of a list of all the activities involved in the project life cycle, the start and finish dates and the sequence of activities. In order to create a project schedule, the project manager first prepares a Work Breakdown Structure (WBS) and estimates the cost, time and man power required to complete each task in the WBS. The schedule helps to track and control project activities, analyze impact of delays and optimize resource utilization.
A project scheduling tool should allow the project manager to do the following:
Define tasks and sub-tasks
A large project might have 4-5 levels of sub-tasks. When the effort and time estimates for the sub tasks are defined with start and end dates, the tool will show the start and end dates of the top level tasks. This will facilitate project monitoring.
Define resources and assign tasks
The project manager should be able to specify the resources (persons, computers) allocated to the project, link these resources with tasks and specify the effort for each task. Given the start date and the resource availability constraints, the tool will automatically calculate the end dates.
Associate the project with a calendar and identify holidays
The tool should allow the project manager to identify the days and the number of hours per day that a resource can work on tasks. National holidays, planned and unplanned leave taken by team members are provided as inputs to the scheduler.
Identify resource allocation clashes
The tool should automatically identify schedule clashes if a resource has been allocated tasks spanning more than the available number of working hours during any time period. The tool should also identify if any resources have not been allocated tasks although they are available to work.
Define dependencies between tasks
There may be some tasks in the project that can be started only when other tasks have been completed. The tool should allow the project manager to specify which tasks can be performed in parallel and which tasks have pre-requisites such as “Task cannot be started before <date>”.
Identify critical paths
Given the list of tasks, dependencies and resources available, the tool will calculate the longest path (sequence of activities) from start to finish and the earliest and latest dates before which each activity on the critical path should be completed in order not to affect the overall schedule. The project may have multiple parallel sub-critical paths. This will help the project manager to identify crash durations (“crash duration” in the context of “project critical path” means, determining the shortest time within which a sequence of tasks can be completed by just adding more resources) and fast-tacks (i.e. performing more activities in parallel to finish the project at an earlier date).
Tools such as the Gantt chart present the schedule as visual models, to enable to stakeholders to get a better idea of the cost, time and scope of the project. The chart shows the tasks, sub tasks, dependencies, duration, start and end dates, percentage of completion of tasks and current status of the project schedule.
The scheduling tool used should support review and updates to the project schedule. A good scheduling tool will provide early warning for schedule variance risks, workload of resources to optimize utilization, progress reports and percentage completion of tasks. It should also support examination of “what-if”, “worst-case” and “best-case” scenarios to assist in decision making while allocating tasks to resources.