Project Scheduling And Resource Leveling - Part 1

May 16, 2008 | Author: PM Hut | Filed under: Resource Leveling, Scheduling

Project Scheduling And Resource Leveling - Part 1 (#1 in the series Project Scheduling And Resource Leveling
By Jorge Dominguez

We all know that in the real world we, as PMs, are given the finish date of the project before we even have a chance to plan for it. This is a good enough reason why we need to get better at scheduling our projects and leveling our finite resources.

Sure, there are tools that allow us to automate the process but a tool is as good as the knowledge of those who use it. All in all, all PMs have a tool and a method by which we create our project schedules. But… we all suffer from common mistakes such as having the wrong dependencies, excessive constraints, inadequate level of detail in the WBS, estimates too granular or inexistent, over allocated resources, etc. Ring a bell?

The tool that is most widely used is MS Project® (MSP). And I am not going to take the time of this article to talk about MSP since this is not the topic. I will, however, mention it as it applies to project scheduling and resource leveling.

The method is what changes from PM to PM. I will explain the “must do” steps and in the correct order.

  • Develop WBS

    Most organizations have a hierarchical structure to break down the work. Typically, it looks like this: Stage, Phase, Task/Deliverable/Milestone. This is a way to organize and define the total scope of the project by decomposing the work to be executed into tasks that the project team can execute and create the required deliverables. The tasks, deliverables or milestones are components that can be scheduled, cost estimated, monitored and controlled.

  • Establish dependencies

    Dependencies are defined so that the work is executed in the proper order. Understand the following task dependency types before you use them; incorrect dependencies will impact the finish date of your schedule and create unnecessary constraints:

    1. Mandatory (hard logic) - Inherent in the nature of the work being done. They often involve physical limitations (i.e.: a test case must be defined before testing)
    2. Discretionary (soft/preferred/preferential logic) - Based on experience, desire or preferences (i.e.: the team decides that they will create the user manual after the first round of testing, although it is not necessary)
    3. External - Based on needs or desires of a party outside the project (i.e.: the server must be purchased before configuring) A network diagram is used to show dependencies in a graphical form. MSP generates a network diagram automatically.
  • Estimate work

    Work is the number of labor units (usually expressed in hours, days or weeks) required to complete a scheduled task. Estimation is equivalent to success. Duration is the total number of work periods (usually expressed as days or weeks) required to complete a scheduled task. When estimating, keep in mind the different task types:

    1. Fixed units (MSP default) - Allows the schedule to calculate the finish date ASAP based on resource availability.
    2. Fixed duration - Used when the priority is to preserve duration. To complete work, assign resources as needed to satisfy the finish date (remember my comment about “knowing” the finish date before we even plan?)
    3. Fixed work - Some project management systems (i.e.: Clarity, formerly Niku) that sit on top of MSP don’t support this type because of the effort driven nature of it and the unpredictable results it may create. So, I have chosen to get used to not to use it at all.

    This is how task types work:

    • If you revise duration in a fixed units task: Work is recalculated, and units are fixed.
    • If you revise duration in a fixed duration task: Work is recalculated, and duration is fixed.
    • If you revise work in a fixed units task: Duration is recalculated, and units are fixed.
    • If you revise work in a fixed duration task: Units are recalculated, and duration is fixed.
    • If you revise units in a fixed units task: Duration is recalculated, and work is fixed.
    • If you revise units in a fixed duration task: Work is recalculated, and units are fixed.

    Task constraint is the next item we need to look at when estimating. You must avoid using moderate and inflexible types. Wrong constraints increase the project risk and extend the finish date:

    1. As late as possible (flexible; default) - For projects scheduled from the finish date. Schedules the latest possible start and finish dates for the task.
    2. As soon as possible (flexible; default) - For projects scheduled from the start date. Schedules the earliest possible start and finish dates for the task.
    3. Finish no earlier than (moderate; avoid) - For projects scheduled from the start date. Indicates the earliest possible date that the task can be completed, and the task cannot finish any time before the specified date.
    4. Finish no later than (moderate; avoid) - For projects scheduled from the finish date. Indicates the latest possible date that the task can be completed, and the task can be finished on or before the specified date.
    5. Start no earlier than (moderate; avoid) - For projects scheduled from the start date. Indicates the earliest possible date that the task can begin, and the task cannot start any time before the specified date.
    6. Start no later than (moderate; avoid) - For projects scheduled from the finish date. Indicates the latest possible date that the task can begin, and the task can start on or before the specified date.
    7. Must finish on (inflexible; avoid) - Indicates the exact date on which the task must finish. Other scheduling parameters such as task dependencies, lead or lag time, and resource leveling become secondary to this requirement.
    8. Must start on (inflexible; avoid) - Indicates the exact date on which the task must begin. Other scheduling parameters such as task dependencies, lead or lag time, and resource leveling become secondary to this requirement.

Jorge Dominguez, PMP®

http://www.Expiriance.com

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[...] Previously in this series Project Scheduling And Resource Leveling - Part 1 [...]

PM Hut » Project Scheduling And Resource Leveling - Part 2 wrote on May 20, 2008 - 7:38 am | Visit Link

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