Timing Constraints in Microsoft Project

A variety of Timing Constraints are only available for Auto Scheduled tasks. All Manually Scheduled tasks are As Soon as Possible (ASAP)

The most important thing to remember is that Timing Constraints have a higher priority on schedule than do links. Unless of course, you turn off that particular scheduling rule in Project Options. (Project Options / Schedule / Scheduling Options for this project / Tasks will always honor their constraint dates)

There are 8 Timing Constraints that can be applied to detail tasks and milestones.

Flexible

• As Soon As Possible (ASAP) - Pushed toward the project start date

• As Late As Possible (ALAP) - Pushed toward the project finish date

Semi-Flexible

• Start No Earlier Than (SNET) a date - The task be pushed out in time, but can not start earlier than a date you enter

• Start No Later Than (SNLT) a date - The task can start earlier than scheduled, but can not start later than a date you enter

• Finish No Earlier Than (FNET) a date - The task can finish later than scheduled, but can not finish earlier than a date you enter.

• Finish No Later Than (FNLT) a date - The task can finish earlier than scheduled, but can not finish later than a date you enter.

Inflexible or Fixed

• Must Start On (MSO) a date - The task must start on a date you enter

• Must Finish On (MFO) a date - The task must finish on a date you enter

Three Timing Constraints are available for Summary Tasks:

• As Soon As Possible

• Start No Earlier Than a date

• Finish No Later Than a date

Scheduling Engine

Behind the scenes of your timeline are an interactive set of features, or rules, that determine how tasks are scheduled. This set of features is often referred to as the scheduling engine.

A partial list of scheduling features or rules include:

• Project Start Date

• Scheduling From the Project Start Date or Project Finish Date

• Calendars

• Schedule Selections in Options

• Task Type (Fixed Duration, Fixed Units, Fixed Work) crossed by Effort Driven (Yes or No)

• Resource Assignments

• Task Mode (Manually or Auto Scheduled)

• Task Constraints

• Links or Dependencies

Schedule built following all of the scheduling rules.

Schedule Logic

Once you have defined the Work Breakdown Structure and Task Requirements, it is time to link tasks together. Linking tasks gives you the opportunity to demonstrate the logic or dependency relationship of tasks.

Microsoft Project and the project management industry as a whole use different language for this activity:

·      Linking tasks

·      Setting dependencies

·      Sequencing deliverables

·      Network diagramming

·      Setting predecessor and successor relationships, etc.

We use the term Task Logic. The idea, which comes from the Project Management Institute, is that in a project there are two types of logic. Hard logic refers to a task that must precede another task, and soft logic illustrates the situation in which you prefer to schedule a task before you schedule another. Often soft logic decisions are made around resource availability.

Task Logic is determined at the Detail task level and it is where plans begin to take shape. Microsoft Project allows you to link summary tasks but if you are interested in correct network diagramming, along with creating and maintaining a critical path for the project, summary linking is inappropriate.

In Microsoft Project, tasks can be linked to one another to demonstrate dependency in various ways; using either the mouse or a dialog box and the keyboard.

Dependency relationships or Task Logic identifies the tasks that must begin or end before other tasks can begin or end.

Once Task Logic is determined, Microsoft Project will calculate the Critical Path for the project.

The schedule of a project is determined by the duration estimates for detail tasks and then the links or dependencies between those tasks.

Note: Factors other than task duration and dependencies can influence schedule, such as resource calendars and timing constraints.

There is a workflow associated with Task Logic.

Workflow in Microsoft Project for Schedule Logic