Saturday, February 9, 2008

Components of Project Scheduling

Have you ever scheduled a job that required more time to complete than you had initially planned for? Did you know that calendars, leads, and lags can help you schedule the appropriate amount of time for a project activity?

In much the same way you use an agenda to keep track of your day-to-day appointments, a project manager uses a calendar to ensure that a project is progressing according to plan.

Project managers use calendars to identify project workdays. Calendars can be altered so weekends and holidays are not included. The arrangement of normal working days, together with non-working days, such as holidays and vacations, and any overtime periods, are used to determine the project completion dates.

To create and use a project calendar, you need to know the range, units and start date.
  • The calendar range is the calendar's span from the start date, up to and including the last date work is performed.
  • Calendar units can be in hours, days, weeks, shifts, and minutes. They are the smallest unit of time used for scheduling the project.
  • The calendar start date is the first calendar unit of the working calendar.
Project managers use two types of calendars when creating a project schedule: project calendars and resource calendars. These two calendars identify periods when work is scheduled to occur.
Project calendars define global project working and non-working periods and affect all project resources. For example, work will only take place on weekdays.

Resource calendars affect specific resources or categories, like people, material or equipment. For example, scheduling around a team member's vacation.

Leads and lags
What would you do if your project was delayed by three weeks, while you were waiting for a necessary piece of equipment to arrive?

Dependencies within a project may require detailed specifications to accurately define the relationships. These specifications are in the form of leads and lags, which are important aspects of the schedule development process.
  • A lead is a modification of a logical relationship allowing for the acceleration of the successor task. For example, in a finish-to-start dependency with a five-day lead, the successor activity can start five days before the predecessor has finished.
  • A lag is a modification of a logical relationship which directs a delay in the successor task. For example, in a finish-to-start dependency with a five-day lag, the successor activity cannot start until five days after the predecessor has finished.
Leads are included in a schedule when an activity must be expedited. Lags are included when an activity needs to be slowed down.
Remember, if your project needs to reflect an assumed delay you may need to implement a lag at the anticipated interval in the schedule. On the other hand, if your project has imposed constraints such as time or future restriction on resources, your schedule may need to include a lead.

Understanding why you must include these components in your resource and project calendars will increase the odds of keeping your project on track, ensuring a successful completion.

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