MS Project

Critical Path Method

Likely the most important feature of Microsoft Project is the calculation of critical path, or Critical Path Method.

Critical Path

The longest path or sequence of project activities that control the earliest a project is expected to finish.

Traditionally, an activity on the critical path has no float or slack, meaning that if the activity is delayed it will delay the finish of the project.

Suppose, for example, that three people are each traveling different routes from point A to point B and would like to know the earliest they can meet together at point B. The person taking the longest path (on the critical path or the longest route) to point B determines the earliest possible time the three can meet together. If that same person takes one hour longer to get to point B than planned, the earliest meeting time is delayed by one hour.

Critical Path Method (CPM)

A simple mathematical method used to determine the duration of the project by calculating the possible paths of activities in a project schedule and identifying the longest path (critical path) in the schedule, or the earliest the project can be expected to finish given everything that must be accomplished.

The Critical Path Method also calculates the amount of float or slack for each activity and sequence or path; identifying how much an activity or sequence of activities can be delayed before delaying the finish of the project.

The Critical Path Method uses a forward pass and backward pass calculation to determine project duration and activity float or slack.

Critical-Path.jpg

Linking In Microsoft Project

There are a variety of terms used to describe linking in Microsoft Project:

  • Linking

  • Setting dependencies

  • Sequencing deliverables

  • Network diagramming

  • Setting predecessor and successor relationships, etc.

There are four different types of links that can be created between tasks:

  • Finish to Start

  • Start to Start

  • Finish to Finish

  • Start to Finish

There are three basic ways to link tasks:

  • Selecting tasks and then clicking the Link command

  • Editing any of the many predecessor or successor fields

  • In the taskbar pane of a Gantt Chart view, Network Diagram view, or a calendar view, click, hold and drag the link command

Linking.jpg

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

Timing-Constraints.jpg

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 built following all of the scheduling rules.