Optimizing Activity Sequencing: Tools and Techniques in Project Management

Sequence Activities is a key process within Project Schedule Management, focusing on the tools and techniques used to determine the order in which project activities will be carried out.

This section explores the tools and techniques used in sequencing project activities, including leads and lags, the Precedence Diagramming Method (PDM), the Project Management Information System (PMIS), and dependency determination and integration. These tools and techniques help in defining logical relationships and dependencies between activities, planning and adjusting activity sequences, and managing potential risks.

The process of sequencing activities interacts with other project management processes in several ways. For instance, the sequence of activities determined during this process feeds into the development of the project schedule. Similarly, the understanding of dependencies gained during this process can inform decision-making in areas such as risk management and resource management. Ultimately, effective sequencing of activities contributes to the successful execution and completion of the project.

Learning Objectives

  • Understand the concepts of lead and lag in project scheduling and their representation in scheduling scenarios and software.
  • Comprehend the application of the Precedence Diagramming Method (PDM) in constructing a schedule model, including the four types of dependencies or logical relationships.
  • Recognize the role of project management information systems, specifically scheduling software, in planning and organizing the sequence of activities.
  • Understand the different types of dependencies in project management, including mandatory, discretionary, internal, and external dependencies.
  • Recognize the role of the project management team in identifying and documenting dependencies during the process of sequencing activities.

Leads And Lags

Leads and lags are essential tools in project scheduling, helping to define the logical relationships between activities.

A lead refers to the amount of time a successor activity can be advanced with respect to a predecessor activity. It allows certain activities to start before the completion of previous activities. For example, in a new office building construction project, landscaping could start 2 weeks prior to the completion of the punch list. This scenario is represented as a finish-to-start with a 2-week lead. In scheduling software, a lead is often represented as a negative value for lag.

On the other hand, a lag is the delay time a successor activity experiences in relation to a predecessor activity. For instance, a technical writing team starting to edit a document 15 days after they begin writing it represents a start-to-start relationship with a 15-day lag. Lags can also be depicted in project schedule network diagrams, indicated by nomenclature such as SS+10, which means a start-to-start relationship with a 10-day lag.

The project management team plays a crucial role in identifying dependencies that may necessitate a lead or a lag to accurately define the logical relationship. However, it's important to note that leads and lags should not be used as a substitute for schedule logic. They are tools to fine-tune the schedule, not to create the fundamental structure of it.

Duration estimates do not incorporate any leads or lags. These are separate considerations that adjust the timing of activities based on the logical relationships between them.

Finally, it's essential to document activities and their associated assumptions. This documentation provides clarity and transparency, helping to ensure that all stakeholders have a clear understanding of the project schedule.

What does a lead in project scheduling refer to?
  1. The delay time a successor activity experiences in relation to a predecessor activity
  2. The time by which a successor activity can be advanced in relation to a predecessor activity
  3. The time by which a predecessor activity can be delayed in relation to a successor activity
  4. The time by which a predecessor activity can be advanced in relation to a successor activity
B) The time by which a successor activity can be advanced in relation to a predecessor activity

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Precedence Diagramming Method

Imagine you're managing a project to build a new website. The project involves several activities, such as designing the layout, writing the content, coding the site, and testing the functionality. The sequence in which these activities are performed is crucial to the project's success. This is where the Precedence Diagramming Method (PDM) comes into play.

PDM is a technique used in project schedule management to construct a schedule model. In PDM, activities like those mentioned above are represented by nodes and are graphically linked by one or more logical relationships. This visual representation clearly shows the sequence in which the activities are to be performed, helping you to manage the project schedule effectively.

PDM encompasses four types of dependencies or logical relationships: Finish-to-start, Finish-to-finish, Start-to-start, and Start-to-finish.

A predecessor activity is an activity that logically precedes a dependent activity in a schedule. Conversely, a successor activity is a dependent activity that logically follows another activity in a schedule.

Finish-to-start is a logical relationship where a successor activity cannot commence until a predecessor activity has been completed. For example, the installation of an operating system on a PC cannot start until the PC hardware assembly is completed.

Finish-to-finish is a logical relationship where a successor activity cannot be completed until a predecessor activity has been completed. An example of this is the writing of a document, which needs to be completed before the editing of the document can be completed.

Start-to-start is a logical relationship where a successor activity cannot start until a predecessor activity has started. An example of this is the leveling of concrete, which cannot begin until the pouring of the foundation has begun.

Start-to-finish is a logical relationship where a successor activity cannot be completed until a predecessor activity has started. An example of this is a new accounts payable system, which has to start before the old accounts payable system can be shut down.

In PDM, Finish-to-Start (FS) is the most frequently used type of precedence relationship, while the Start-to-Finish (SF) relationship is seldom used. However, SF is included in PDM to provide a comprehensive list of relationship types.

Reflecting back on our website development project, it's important to note that while two activities, such as coding and testing, can simultaneously have two logical relationships, such as Start-to-Start (SS) and Finish-to-Finish (FF), it is not advisable to have multiple relationships between the same activities in project management.

When multiple relationships exist, a decision should be made to select the logical relationship with the highest impact. For instance, you might prioritize the Finish-to-Finish relationship between coding and testing, ensuring that testing is not completed until all coding is finished. Additionally, closed loops are not recommended in the establishment of logical relationships in project management. By following these guidelines, you can effectively use PDM to manage your project schedule.

What is the Precedence Diagramming Method (PDM) primarily used for in project management?
  1. To construct a schedule model
  2. To estimate project costs
  3. To identify project risks
  4. To manage project stakeholders
A) To construct a schedule model

Project Management Information System (Pmis)

Project Management Information Systems (PMIS) play a crucial role in project schedule management, particularly in the sequencing of activities. These systems incorporate scheduling software that aids in planning, organizing, and adjusting the sequence of activities, ensuring that project tasks are carried out in an efficient and effective manner.

One of the key capabilities of scheduling software within a PMIS is the ability to insert logical relationships and lead and lag values. Logical relationships define the sequence in which project activities should be carried out, while lead and lag values indicate the amount of time that must pass between these activities. By incorporating these elements, scheduling software can help project managers develop a realistic and achievable project schedule.

In addition to inserting logical relationships and lead and lag values, scheduling software can also differentiate between different types of dependencies. Dependencies refer to the relationships between project activities, where the start or finish of one activity is dependent on the start or finish of another. By identifying and differentiating these dependencies, scheduling software can help project managers anticipate potential scheduling issues and adjust the project schedule accordingly.

What is the primary purpose of a Project Management Information System (PMIS) in sequence activities?
  1. To provide a communication platform for the project team
  2. To aid in planning, organizing, and adjusting the sequence of activities
  3. To provide a detailed cost estimate of the project
  4. To record additional information on existing or new stakeholders
B) To aid in planning, organizing, and adjusting the sequence of activities

Dependency Determination And Integration

Dependencies in project management serve as the invisible threads that weave together activities, dictating the order in which they must be executed. These relationships come in four main flavors: mandatory, discretionary, internal, and external, each carrying its unique characteristics and implications.

Mandatory dependencies, also known as hard logic or hard dependencies, are legally or contractually required or inherent in the nature of the work. They often involve physical limitations, such as the need to lay a foundation before building a wall. The project team determines these dependencies during the process of sequencing activities. It's important to note that mandatory dependencies are not the same as schedule constraints in the scheduling tool.

Discretionary dependencies, also referred to as preferred logic, preferential logic, or soft logic, are established based on knowledge of best practices or specific project aspects. They allow for a specific sequence, even if other sequences are acceptable, to reduce overall project risk. The project team also determines these dependencies during the process of sequencing activities. Discretionary dependencies should be fully documented as they can create arbitrary total float values and limit later scheduling options. When fast tracking techniques are used, these dependencies should be reviewed and considered for modification or removal.

External dependencies involve a relationship between project activities and non-project activities. These dependencies are typically outside of the project team's control. For example, a software project may depend on the delivery of hardware from an external source. The project management team identifies these dependencies during the process of sequencing activities.

Internal dependencies involve a precedence relationship between project activities and are generally within the project team's control. For instance, a team cannot test a machine until they assemble it, which is known as an internal mandatory dependency. The project management team identifies these dependencies during the process of sequencing activities.

Grasping the nuances of these diverse types of dependencies is a cornerstone of effective project schedule management. This understanding equips the project team with the ability to sequence activities with precision, manage risks proactively, and make enlightened decisions about the project's execution.

What is a mandatory dependency in project management?
  1. A relationship between project activities and non-project activities
  2. A dependency that is legally or contractually required or inherent in the nature of the work
  3. A dependency established based on knowledge of best practices or specific project aspects
  4. A dependency that involves a precedence relationship between project activities
B) A dependency that is legally or contractually required or inherent in the nature of the work