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Henry Laurence Gantt, A.B., M.E. ( November 1919) was a mechanical engineer and management consultant who is most famous for developing the Gantt chart in 1917, besides a number of others charts. The first Gantt charts were employed on major infrastructure projects including the Hoover Dam. The special type of horizontal bar chart that provides a graphical overview and schedule of all activities, elements and dependencies of a project or program. A Gantt chart is constructed with a horizontal axis representing the total time span of the project, broken down into increments (for example, days, weeks, or months) and a vertical axis representing the tasks that make up the project. Horizontal bars of varying lengths represent the sequences, timing, and time span for each task.

3 Information Technology Project Management, Fourth Edition Gantt Chart for Software Launch Project Symbols include: ◦ Black diamonds: Milestones ◦ Thick black bars: Summary tasks ◦ Lighter horizontal bars: Durations of tasks ◦ Arrows: Dependencies between tasks

4 Information Technology Project Management, Fourth Edition Sample Tracking Gantt Chart

5 Information Technology Project Management, Fourth Edition SMART Criteria Milestones should be: ◦ Specific ◦ Measurable ◦ Assignable ◦ Realistic ◦ Time-framed

Usage of a Gantt Chart: Display an overview of project activities. Plan project activities. Work out the critical path. Give you a basis to schedule when the tasks should be carried out. Allocate resources. Communicate project activities. Coordinate and manage project activities. Monitor the progress of project activities.

Strengths of the Gantt Chart. Benefits Good graphical overview. Common technique. Easy to understand. Small to medium size projects with no more than about 30 activities. Can be supported by special project planning software to facilitate complex calculations and complex dependencies and conduct what-if analyses.

Limitations of the Gantt Chart. Disadvantages  Projects are often considerably more complex than can be communicated effectively with a Gantt chart.  Gantt charts only represent part of the triple constraints (time, cost and scope) of projects, because they focus primarily on schedule management (time). Compare: Cost-Benefit Analysis.Cost-Benefit Analysis  Gantt charts do not represent the size of a project or the relative size of work elements, therefore the magnitude of a behind-schedule condition is easily misunderstood.  Software. Although project management software can show schedule dependencies as lines between activities, displaying a large number of dependencies may result in a cluttered or unreadable chart. Avoid using (heavy) grids in Gantt software as they distract the attention.

9 Program Evaluation and Review Technique (PERT) The Program (or Project) Evaluation and Review Technique, commonly abbreviated PERT, is a statistical tool, used in project management, that is designed to analyze and represent the tasks involved in completing a given project. First developed by the United States Navy in the 1950s, it is commonly used in conjunction with the critical path method or CPMproject managementprojectUnited States Navycritical path method PERT is a network analysis technique used to estimate project duration when there is a high degree of uncertainty about the individual activity duration estimates. PERT uses probabilistic time estimates: ◦ Duration estimates based on using optimistic, most likely, and pessimistic estimates of activity durations, or a three-point estimate.

PERT was developed primarily to simplify the planning and scheduling of large and complex projects. It was developed for the U.S. Navy Special Projects Office in 1957 to support the U.S. Navy's Polaris nuclear submarine project It was able to incorporate uncertainty by making it possible to schedule a project while not knowing precisely the details and durations of all the activities. It is more of an event-oriented technique rather than start- and completion-oriented, and is used more in projects where time, rather than cost, is the major factor. It is applied to very large-scale, one-time, complex, non-routine infrastructure and Research and Development projects

11 Information Technology Project Management, Fourth Edition PERT Formula and Example PERT weighted average = optimistic time + 4X most likely time + pessimistic time 6 Example: PERT weighted average = 8 workdays + 4 X 10 workdays + 24 workdays = 12 days 6 where: optimistic time= 8 days most likely time = 10 days pessimistic time = 24 days Therefore, you’d use 12 days on the network diagram instead of 10 when using PERT for the above example.

12 Information Technology Project Management, Fourth Edition Determining the Critical Path for Project X

Advantages PERT chart explicitly defines and makes visible dependencies PERT facilitates identification of the critical path and makes this visible PERT facilitates identification of early start, late start, and slack for each activity, PERT provides for potentially reduced project duration due to better understanding of dependencies leading to improved overlapping of activities and tasks where feasible. The large amount of project data can be organized & presented in diagram for use in decision making. Disadvantages There can be potentially hundreds or thousands of activities and individual dependency relationships The network charts tend to be large and unwieldy requiring several pages to print and requiring special size paper The lack of a timeframe on most PERT/CPM charts makes it harder to show status although colours can help (e.g., specific colour for completed nodes) When the PERT/CPM charts become unwieldy, they are no longer used to manage the project.

Gantt Chart versus PERT  Unlike the Gantt Chart, the Program Evaluation and Review Technique (PERT) has no calendar, so you can not see precisely when the activities should be performed.  On the other hand, the dependencies between the activities in PERT are easier to follow. This is why for larger projects, usually PERT is preferable.  Actually PERT uses multiple time estimates for each activity to allow for variation in activity times. The activity times are assumed to be random, with assumed probability distribution ("probabilistic").  They are represented by arrowed lines between nodes or circles.