Project Time Management - Sequence Activities

This process identifies and documents relationships among the project activities to define the logical sequence of work to obtain the greatest efficiency.

Each activity and milestone should be connected to something before (predecessor) and something after (successor) it. The relationship of these activities can be connected with the following:

• Finish-to-start (FS)  - an activity that is finished will start another one at the same time
• Start-to-start  (SS)- an activity that starts will start another one at the same time
• Start-to-finish (SF) - an activity that starts will finish another one at the same time
• Finish-to-finish  (FF) - an activity that ends will ends another one at the same time

Lets take a look at the Inputs, Tools and Techniques, and Outputs of this process.

1) Schedule Management Plan

• Identifies the scheduling method and tool to be used for the projects to guide the sequence of activities

2) Activity List

• Contains all schedule activities required on the project with their dependencies and constraints.

3) Activity Attributes

• Describes a necessary sequence of events
• Defines predecessor or successor relationships

4) Milestone List

• Contains scheduled dates for specific milestones

5) Project Scope Statement

• Information in the scope statement that can influence sequence activities may include:
• Product scope description
• Product characteristics (physical layout of a plant or subsystems interfaces on software project) 
• Project deliverables
• Project constraints 
• Project assumptions

6) Enterprise Environmental factors

• Factors that may influence Sequence Activities may include:
• Government or industry standards
• Project Management Information Systems (PMIS) 
• Scheduling tool
• Company work authorization systems

7) Organizational Process Assets

Factors that may influence Sequence Activities may include:

• Project files from corporate knowledge base
• Existing policies, procedures and guidelines
• Templates

8) Precedence Diagramming Method (PDM)

• Technique used for constructing a schedule model where activities are graphically linked by one or more logical relationships to show the sequence of activities to be performed.
• Activity-on-node (AON) - method that represents a precedence diagram  

9) Dependency Determination

• There are four different types of dependencies and two can be applicable at the same time (mandatory internal dependencies, discretional external dependencies, etc.) 
• Mandatory dependencies - legally or contractually required. They are also known as hard logic or hard dependencies. They are assigned by the project team and shouldn't be confused with assigning schedule constraints in the scheduling tool. 
• Discretionary dependencies - established based on knowledge of best practices where a specific sequence is desired. They have to be documented as they cause arbitrary total float values and can limit scheduling options later. They are also known as preferred logic, preferential logic or soft logic. 
• External dependencies - involves relationships between project activities and non-project activities that are outside of the teams control. An example is that you need some hardware equipment from an outside vendor before you can add software to it. The team must determine what dependencies are external and process those sequence of activities. 
• Internal dependencies - have a precedence (something more important) relationship between project activities and are inside the teams control. 

10) Leads and Lags

• Lead is the amount of time whereby a successor activity can be advanced with respect to a predecessor activity. 
• Lag is the amount of time whereby a successor activity will be delayed with respect to a predecessor activity. 

11) Project Schedule Network Diagrams

• A graphical representation of the logical relationships among the project schedule activities. It can be created manually or using project management software. A summary narrative and any unusual activity sequence may be included with this diagram. 

12) Project Document Updates

• Documents that you may update can include:
• Activity lists
• Activity attributes
• Milestone list
• Risk register

Source: PMBOK 5th ed.