Activity sequencing

Activity sequencing involves determining the order in which project activities should be performed to achieve project objectives efficiently. Let’s illustrate activity sequencing with examples from both Engineering, Procurement, and Construction (EPC) projects and Information Technology (IT) projects:

  1. EPC Project: Construction of a BridgeExample Activities:
    1. Site Preparation
    2. Foundation Construction
    3. Structural Steel Erection
    4. Concrete Deck Installation
    5. Pavement Construction
    6. Installation of Guardrails and Signage
    7. Final Inspection and Handover
    Activity Sequencing:
    • Site Preparation must precede Foundation Construction to clear the area and prepare the ground for foundation work.
    • Foundation Construction should be completed before Structural Steel Erection to provide a stable base for the bridge structure.
    • Structural Steel Erection typically precedes Concrete Deck Installation, as the steel framework forms the skeleton for supporting the deck.
    • Concrete Deck Installation should be completed before Pavement Construction to provide a surface for road traffic.
    • Installation of Guardrails and Signage usually occurs after Pavement Construction to ensure safety measures are in place.
    • Final Inspection and Handover occur after all construction activities are completed to verify quality and readiness for use.
  2. IT Project: Development of a Software ApplicationExample Activities:
    1. Requirements Gathering
    2. UI/UX Design
    3. Backend Development
    4. Database Integration
    5. Testing and Debugging
    6. User Acceptance Testing
    7. Deployment
    Activity Sequencing:
    • Requirements Gathering should precede UI/UX Design to define the functionality and user interface requirements.
    • UI/UX Design typically precedes Backend Development to provide specifications for implementing the user interface.
    • Backend Development should be completed before Database Integration to ensure that the application logic is in place before integrating with the database.
    • Testing and Debugging occurs after Backend Development and Database Integration to identify and resolve any issues with the software.
    • User Acceptance Testing follows Testing and Debugging to validate that the software meets user requirements.
    • Deployment occurs after successful completion of all development and testing activities, ensuring that the software is ready for production use.

In both examples, activity sequencing is essential for ensuring that project activities are performed in the correct order to minimize delays, optimize resource utilization, and achieve project objectives effectively. By identifying dependencies between activities and sequencing them logically, project managers can create a structured plan for executing the project successfully.

The 4 types of dependencies among tasks

In project management, there are four main types of dependencies among activities, each of which describes a relationship between two or more project tasks. These dependencies help determine the sequencing of activities and the order in which they should be performed. Here are the four types of dependencies:

  1. Finish-to-Start (FS): This is the most common type of dependency, where the start of one activity depends on the completion of another activity. In other words, Activity A must finish before Activity B can start. For example, pouring concrete (Activity B) cannot begin until the foundation is fully excavated (Activity A) and finished.
  2. Start-to-Start (SS): In this type of dependency, the start of one activity depends on the start of another activity. Both activities can start simultaneously or with a time lag. For example, two teams may need to start their respective tasks (Activity A and Activity B) simultaneously to ensure that they can coordinate their work effectively.
  3. Finish-to-Finish (FF): This dependency means that the completion of one activity is dependent on the completion of another activity. Both activities must finish at the same time or with a time lag. For example, the testing phase (Activity B) may depend on the completion of the development phase (Activity A), ensuring that testing can begin as soon as development is finished.
  4. Start-to-Finish (SF): This is the least common type of dependency, where the start of one activity depends on the completion of another activity. In other words, Activity A must start before Activity B can finish. This type of dependency is rarely used in practice and can be confusing, so it’s best to avoid it whenever possible.

Understanding these dependencies is crucial for creating a realistic project schedule, identifying critical paths, and managing project risks effectively. By accurately sequencing activities based on their dependencies, project managers can ensure that the project progresses smoothly and is completed on time and within budget.

Out of these the most widely occuring dependency is ‘finish to start’, followed by ‘start to start’ and ‘finish to finish’

Example from EPC project

Let’s illustrate examples of the four types of dependencies within Engineering, Procurement, and Construction (EPC) projects:

  1. Finish-to-Start (FS) Dependency:Example: Construction of a Power Plant
    • Activity A: Excavation and Site Preparation
    • Activity B: Foundation Construction
    • Dependency: Activity B (Foundation Construction) cannot start until Activity A (Excavation and Site Preparation) is completed. The excavation must finish before the foundation can be constructed.
  2. Start-to-Start (SS) Dependency:Example: Installation of Electrical Wiring
    • Activity A: Cable Tray Installation
    • Activity B: Electrical Wiring Installation
    • Dependency: Activity B (Electrical Wiring Installation) can start as soon as Activity A (Cable Tray Installation) starts. Both activities need to start simultaneously to ensure that wiring can be installed promptly once the cable trays are in place.
  3. Finish-to-Finish (FF) Dependency:Example: Testing and Commissioning
    • Activity A: Equipment Installation
    • Activity B: Testing and Commissioning
    • Dependency: Activity B (Testing and Commissioning) depends on the completion of Activity A (Equipment Installation). Testing can only commence after all equipment has been installed successfully.
  4. Start-to-Finish (SF) Dependency:Example: Material Procurement and Delivery
    • Activity A: Material Procurement
    • Activity B: Delivery of Materials
    • Dependency: Activity A (Material Procurement) must start before Activity B (Delivery of Materials) finishes. For instance, if materials are procured for delivery within a specific timeframe, the procurement process must begin early enough to ensure timely delivery.
Example from IT project

Here are examples of the four types of dependencies in the context of IT projects:

  1. Finish-to-Start (FS):
    • Example: In a software development project, the deployment of a new feature (Activity B) depends on the completion of coding and testing (Activity A). The feature cannot be deployed until it has been fully developed and tested.
  2. Start-to-Start (SS):
    • Example: In the development of a website, the creation of frontend UI components (Activity A) may start simultaneously with the setup of the backend server (Activity B). Both activities need to commence together to ensure the frontend and backend components are developed in parallel.
  3. Finish-to-Finish (FF):
    • Example: In a data migration project, the validation and verification of migrated data (Activity B) depend on the completion of the data extraction process (Activity A). The verification process can only begin once all data has been successfully extracted.
  4. Start-to-Finish (SF):
    • Example: In a software testing project, the start of documenting test cases (Activity A) may be dependent on the completion of executing initial test cases (Activity B). The documentation process cannot begin until the initial testing phase has started and produced results to document.

In each of these examples, the type of dependency influences the sequencing of activities and impacts the overall project schedule. Understanding and managing these dependencies are essential for effective project planning and execution