Scheduling Tools
Here are some tools and techniques for combining these inputs to develop the schedule:- Schedule Network Analysis – This is a graphic representation of the project's activities, the time it takes to complete them, and the sequence in which they must be done. Project management software is typically used to create these analyses – Gantt charts and PERT Charts are common formats.
- Critical Path Analysis – This is the process of looking at all of the activities that must be completed, and calculating the 'best line' – or critical path – to take so that we'll complete the project in the minimum amount of time. The method calculates the earliest and latest possible start and finish times for project activities, and it estimates the dependencies among them to create a schedule of critical activities and dates. Learn more about Critical Path Analysis.
- Schedule Compression – This tool helps shorten the total duration of a project by decreasing the time allotted for certain activities. It's done so that we can meet time constraints, and still keep the original scope of the project. We can use two methods here:
- Crashing – This is where we assign more resources to an activity, thus decreasing the time it takes to complete it. This is based on the assumption that the time we save will offset the added resource costs.
- Fast-Tracking – This involves rearranging activities to allow more parallel work. This means that things we would normally do one after another are now done at the same time. However, do bear in mind that this approach increases the risk that we'll miss things, or fail to address changes.
- Help us to plan out the tasks that need to be completed
- Give us a basis for scheduling when these tasks will be carried out
- Allow us to plan the allocation of resources needed to complete the project, and
- Help us to work out the critical path for a project where we must complete it by a particular date.
Sequential and parallel activities:
An essential concept behind project planning (and Critical Path Analysis) is that some activities are dependent on other activities being completed first. As a shallow example, it is not a good idea to start building a bridge before we have designed it!These dependent activities need to be completed in a sequence, with each stage being more-or-less completed before the next activity can begin. We can call dependent activities 'sequential' or 'linear'.
Other activities are not dependent on completion of any other tasks. These may be done at any time before or after a particular stage is reached. These are nondependent or 'parallel' tasks.
Gantt charts are useful tools for planning and scheduling projects. They allow we to assess how long a project should take, determine the resources needed, and lay out the order in which tasks need to be carried out. They are useful in managing the dependencies between tasks.
When a project is under way, Gantt charts are useful
for monitoring its progress. We can immediately see what should have been
achieved at a point in time, and can therefore take remedial action to bring
the project back on course. This can be essential for the successful and
profitable implementation of the project.
Taking its name from early project management innovator Henry L. Gantt, the
basic Gantt chart is an easy way to document schedules. It is a horizontal-bar
schedule showing activity start, duration, and completion. It shows the
connection between events and the calendar, and provides a graphical analog of
the activity duration.The Gantt schedule can illustrate the relationship between work activities having duration, events without duration that indicate a significant completion, and milestones that represent major achievements or decision points. Various annotations can be used to communicate the progress of the project effort compared to the baseline plan, as well to depict in a graphical way areas where there are modified expectations from the baseline plan.
Once a Gantt schedule has been established for a project, progress should be periodically plotted against the baseline schedule. If different functional areas are involved in a project, each area may need its own detailed schedules to support the project master schedule. In such cases it is important that working schedules be linked to a common master schedule in a way that they can be easily updated. Each activity or event on the schedule should have a responsible individual assigned, so there is clear ownership and so schedule status can be updated without a lot of fuss.
Planning, Scheduling & Control
Planning, Scheduling (or organizing) and Control are considered to be basic Managerial functions, and CPM/PERT has been rightfully accorded due importance in the literature on Operations Research and Quantitative Analysis.Far more than the technical benefits, it was found that PERT/CPM provided a focus around which managers could brain-storm and put their ideas together. It proved to be a great communication medium by which thinkers and planners at one level could communicate their ideas, their doubts and fears to another level. Most important, it became a useful tool for evaluating the performance of individuals and teams.
There are many variations of CPM/PERT which have been useful in planning costs, scheduling manpower and machine time. CPM/PERT can answer the following important questions:
How long will the entire project take to be completed? What are the risks involved?
Which are the critical activities or tasks in the project which could delay the entire project if they were not completed on time?
Is the project on schedule, behind schedule or ahead of schedule?
If the project has to be finished earlier than planned, what is the best way to do this at the least cost?
The Framework for PERT and CPM
Essentially, there are six steps which are common to both the techniques. The procedure is listed below:- Define the Project and all of its significant activities or tasks. The Project (made up of several tasks) should have only a single start activity and a single finish activity.
- Develop the relationships among the activities. Decide which activities must precede and which must follow others.
- Draw the "Network" connecting all the activities. Each Activity should have unique event numbers. Dummy arrows are used where required to avoid giving the same numbering to two activities.
- Assign time and/or cost estimates to each activity
- Compute the longest time path through the network. This is called the critical path.
- Use the Network to help plan, schedule, monitor and control the project.
Non-critical activities can be re planned, rescheduled and resources for them can be reallocated flexibly, without affecting the whole project.
Five useful questions to ask when preparing an activity network are:
- Is this a Start Activity?
- Is this a Finish Activity?
- What Activity Precedes this?
- What Activity Follows this?
- What Activity is Concurrent with this?
When work is delegated like this, the need for constant feedback and co-ordination becomes an important senior management pre-occupation.
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