Project Management - Ch. 6 Summary

after a plan is developed for a project, the next step is to develop a project schedule. The first step in this process is to estimate how long each activity will take, from the time it is started until the time it is finished. It's a good practice to have the person who will be responsible for negativity estimate its duration; however, with larger projects this is often not possible.

And activities duration estimate must be based on the quantity of resources expected to be used on the activity. The estimate should be aggressive, yet realistic. A consistent time base, such as hours or days or weeks, should be used for all the activity duration estimates.

The earliest are in earliest finish (ES and EF) Times and the latest start in latest finish (LS and LF) times can be calculated for each activity. The ES and EF times are calculated by working forward through the network. The earliest start time for an activity is calculated on the basis of the projects estimated start time and the duration estimates for proceeding activities. The earliest finish time for an activity is calculated by adding activities duration estimate to the activities early start time. The earliest start time for particular activity must be the same as or later than the latest of all the earliest finish times of all the activities leading directly to that particular activity.

The LS and LF times are calculated by working backward through the network. The latest finish time for an activity is calculated on the basis of the projects required completion time and the duration estimates for succeeding activities. The latest our time is calculated by subtracting the activities duration estimate from the activities latest finish time. The latest finish time for particular activity must be the same as our earlier than the earliest of all the latest start times of all the activities emerging directly from that particular activity.

The total slack for particular path through the network is common to and shared among all activities on that path. If it is positive, it represents the maximum amount of time that the activities on a particular path can be delayed without jeopardizing completion of the project by the required time. If total slack is negative, it represents the amount of time that the activities of the path must be accelerated in order to complete the project by the required time. If it's a row, the activities on that path do not need to be accelerated but cannot be delayed. The critical path is the longest (most time-consuming) half of activities in the network diagram and represents a series of activities that cannot be postponed without delaying the entire project.

Scheduling the development of an information system is a challenging process. Unfortunately, such scheduling is often done in a haphazard manner, and thus a large percentage of IS projects are finished much later than originally promised. One of the most important factors and effective scheduling is arriving at activity duration estimates that are as realistic as possible. The project manager should be aware of the common problems that often push IS development projects beyond their scheduled completion date. Project management software packages can help with the scheduling process.

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