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Sequencing the Project Activities

This article is dedicated to the proper sequencing of project activities. The sequencing of activities is the process of identifying and documenting relationships among the  project activities. This process defines the logical sequence of work. All the project constraints will be taken into consideration.

The total Project Time Management Processes are as follows:

sequencing-project-activities

Figure: Sequence activities, Develop schedule, and Control schedule activities are covered in Project Scheduling Professional™

As you can see from the graph above, the process ,sequence activities, is the second step in the development of a schedule. I recommend to adhere to this sequence because this creates control of the process.

What are the constraints and inputs for the process Sequencing activities?

The major input and constraints are: the schedule management plan, activity list, activity attributes, milestone lists, project scope statement, Enterprise Environmental Factors and the Organizational Process Assets. These are detailed below:

The Activity List

This contains all the schedule activities required on the project. This activity list is the output of the process: define activities.  The define activities are the result of the decomposition of the scope and detailed in the Work Breakdown Structure (WBS).

The Activity Attributes

These may describe the necessary sequence of event and predecessor or successor relationships. The attributes may consist of ID, WBS, Phase, Area, Part, Responsible, Activity Codes, Cost Resources, identifier and many others. They also can carry the type of activities such as, level of Effort, WBS summary, Resource dependent, Task Dependent and Milestones. It is recommended to include User defined identifiers so that data from outside applications can be loaded into the schedule.

The Milestone List

This contains the specific milestones, which may influence the way activities are sequenced. A milestone list is a complete list of all major events in the schedule. They have the same structures as the attributes but have a zero duration.

The Project Scope Statement

This describes the scope description and characteristic of the project and this may affect the activity sequencing.

Enterprise Environmental Factors

These factors that can influence the sequencing of activities. These can be industry standards, project management information systems, scheduling tools and authorization systems.

The Organizational Process Assets

These are the organizational assets that can influence the sequencing of activities, such as scheduling methodology or pre-defined scheduling container templates.

So, all the constraints and major inputs have been taken into account and now is time to look at the  tools and techniques that we can use to effectively sequence activities.

Tools and Techniques

The Precedence Diagramming Network is a graphical presentation of logical relationships. The project schedule network can be produced manually or with project management software.

The Precedence Diagramming Method (PDM) includes four types of relationships.

Sequencing activities relationships

These are:

Finish to Start (FS)

This relationship type is used when a activity must be finished before the successor can start.

Finish to Finish (FF)

This relationship type is used when a successor activity cannot finish until a predecessor has finished.

Start to Start (SS)

This relationship type is used when a successor activity cannot start until a predecessor has started

Start to Finish (SF)

This relation type is used when a successor activity cannot finish until a predecessor has started.

Lags and leads

A lag is the amount of time whereby a successor’s activity is delayed with respect to a predecessor activity. A lead is the amount of time whereby a successor activity can be advanced with respect to a predecessor.

I suggest that lags and leads are used sparingly. These can distort the forward and backward pass and therefore the results are unpredictable. Recommended practice is to add activities to properly maintain the finish start relationship.

Precedence Network Diagram

The Precedence Network Diagram is the output from the sequencing process.

So, let’s make simple network diagram with 6 activities.

We have a small Network Diagram that shows that the Activities B, C, and D cannot start until Activity A is finished. Activity E cannot starts until C is finished , and F cannot start until B, E and D all are finished.

Sequencing activities network

Now you can see that the activities are properly sequenced.

Good luck and trust that the process of sequencing of activities is clear.

 

Reference:

  • A guide to the PROJECT MANAGEMENT BODY OF KNOWLEDGE (PMBOK GUIDE fight edition)
  • Managing Projects as Investments by Stephen A. Devaux