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Three kinds of schedules are normally encountered by project managers:  personnel, performance, and financial. Performance schedules are usually constrained by their beginning and ending dates for each task, and provide the general structure for rest of the project’s schedules.  Financial schedules handle the distribution and budgeting of financial resources for those performance tasks over time.  This cost schedule is one of the major drivers of the overall project budget.

The project manager needs to view everything holistically as each of these schedules interrelate.  Project Managers use PERT and Gantt charts to help schedule the tasks within the project.  They can additionally be used to convey progress and plans with the end customer and team members.  The Project Manager needs to decompose the work into smaller chunks, generally called task decomposition, before any of these tools can be leveraged for scheduling.  The customer also needs to provide their insight into the schedule and deadlines as well, as they will understand interim dates and priorities far better than a project manager unfamiliar with their business. Even though these charts aren’t a cure-all for every project dilemma, these are certainly some of the best tools for project scheduling a project manager can get their hands on.

Pert Chart

The Program Evaluation and Review Technique (PERT) was designed in the 1950’s. PERT has always been an event-driven scheduling technique.   On a PERT chart, the labels are placed on the nodes within the project diagram.

They have generally found uses in aerospace and R & D projects since those projects deal with a great deal of uncertainty for each activity. PERT leveraged an aspect of its predecessor, the critical path method (CPM), another activity-oriented scheduling tool, which placed the activity label on the arrow from node to node in the PERT diagram.  This allowed the the manager to get a scheduled duration for each activity in the chart.  Today, most PERT systems are hybridized, leveraging the best of both the PERT and CPM worlds at the manager’s command. A PERT chart looks like a lot of boxes connected by arrows, basically, is more like flow diagrams to the naked eye.

Gantt Chart

Schedules at the task level generally use a time-driven linear layout or bar chart. The Gantt chart does just this. If you need to show the time-phased requirements for tasks and workers across an entire project, then a Gantt chart is the perfect choice to convey these.  Gantt charts are similar to the PERT/CPM hybrids, but that are far simpler for a team to understand since they make the project’s critical path and milestones so plainly visible.

Understanding what a Gantt chart does, is critical to is effective use.  Take Microsoft Project’s Gantt chart tool, for example.  If you understand the work breakdown of your project and the schedule of each of the tasks therein, you can take advantage of this tool to show the way the project should proceed, when the milestones are expected to be attained, and then you put the Gantt chart together to paint that picture.  You can also use Excel to make this kind of chart by using the stacked bar chart type feature or conditional formatting.  Given that there are so many other very effective project management tools on the market today capable of making Gantt charts with ease, using excel is seldom the best bet.  Regardless of which software you use, you will need to know exactly what your activities are for the project, and which activities hinge on others getting done.  You will essentially put together the timeline for the critical path items and those which are inflexible for whatever reason, and backfill until everything occurs in the order in which you need it to for the project to get finished on time.

In spite of the best laid plans, frequently project overruns occur. At that time whatever scheduling tools are used must be adjusted. It takes human intelligence to make it all work, no matter how sophisticated the software.

Even with the help of charts, it is really up to the Project Manager to understand the flow of work for the project. The best software is only as good as the mind that uses it.