Selecting the suitable project delivery model significantly influences the success of an enterprise IT project. It affects how teams collaborate, adapt, and deliver value to stakeholders. Table 8 below offers guidance for choosing the most suitable delivery model—Waterfall, Agile, or Hybrid—based on specific project attributes. By assessing factors such as project type, scope, time, cost, quality, delivery, and constraint priorities, informed decisions can be made to meet a project's unique requirements.

Commentary: Quality in Agile

Agile models develop, test, and implement components to deliver value early and progressively through sprint cycles. This often results in an incomplete or partial product with no predetermined end date for providing the full scope.

Commentary: Constraint priority in Waterfall

Once the project scope and timeline are defined, these elements become primary constraints against which all project decisions are measured. Changes to scope require formal processes and can significantly impact the timeline and costs.

Commentary: Constraint priority in Agile

Agile prioritises delivering a high-value product or partial project scope components within time-boxed sprints. There is no guarantee that the sprint's scope will be completed, and any undelivered scope will return to the product backlog for consideration in future sprints.

Commentary: Constraint priority in Hybrid

The Hybrid model combines the predictability of Waterfall’s fixed scope and timeline with Agile's flexibility and quality focus. It starts with a clear project scope and schedule while allowing for a balance between scope, quality, and time adjustments.

Following the comparative overview of the Waterfall, Agile, and Hybrid delivery models, the following case study presents a real-world application of Waterfall in a high-stakes financial services environment.

Background

Horizon Bank embarks on a 3-year project to replace its legacy dollar banking system with a modern solution to enhance customer service and ensure compliance with updated regulations. The complex project involves intricate integrations with existing systems, data migration, and organisational change management. Given the project's fixed budget, tight timeline, and the critical nature of the financial sector, the Waterfall model is selected for its structured, sequential approach to project delivery.

Project Type and Scope

The project involves significant custom development to meet regulatory requirements and enhance functionalities. The scope is clearly defined upfront, covering essential high-level items:

• Technology replacement: Deployment of the new digital banking system and integration with third-party financial services and APIs.
• Data migration: Comprehensive mapping and cleansing of legacy data and customer and transaction records migration while ensuring data integrity and regulatory compliance.
• Process alignment: Redesign of banking processes to match the capabilities of the new system, with workflows developed to enhance efficiency. 
• Organisational change management: Stakeholder engagement and employee to support the system transition. 
• Decommissioning old systems and processes: Phased decommissioning of the legacy system, integrated systems, and supporting processes post-implementation.

Sequential Phases

The project is executed through the following sequential phases:

• Initiation: Initial assessments confirm the need for a new system, and the business case justifies the project's cost and compliance benefits. Based on the clear, fixed scope, stakeholders approve the project.
• Planning: A detailed project plan is developed, outlining requirements, timelines, and resource allocations. Risk management is emphasised regarding regulatory compliance and potential customer service impacts during the transition. A formalised change control process is established to manage any scope changes.
• Execution: Development begins according to the established plan, focusing on designing the system and completing coding. Testing follows a linear progression, ensuring that each component is fully validated before moving to the next stage of development. Testing includes unit, integration, system, and user acceptance testing, ensuring compliance and functionality are verified before advancing.
• Monitoring and Controlling: Regular reviews ensure the project stays within scope, budget, and schedule. Risks identified in the planning phase, particularly regarding data migration and compliance, are continuously monitored. Any deviations are managed through formal change requests, keeping the project on track without sacrificing control over critical deliverables.
• Closing: The new system is rolled out, with comprehensive user training provided to ensure employees can effectively use the latest features. A final review evaluates the project's success in meeting its original goals, ensuring the system aligns with regulatory standards and the bank's operational needs. The legacy system is decommissioned, and the transition is carefully managed to avoid service disruptions.

Quality Assurance

Quality is strictly managed throughout the project. Each phase includes rigorous validation to ensure the system meets all predefined specifications. This reduces the risk of defects or non-compliance, which is particularly important in the highly regulated financial industry. Waterfall's structured approach ensures thorough testing before final delivery, with no significant surprises at the end.

Conclusion

This case study illustrates how the Waterfall model’s linear, structured approach is well-suited for projects with clearly defined requirements and fixed constraints. Horizon Bank’s successful navigation of the complexities of regulatory compliance, system integration, and data migration demonstrates the value of Waterfall in achieving the timely, budget-controlled replacement of its dollar banking system to a digital banking system.

While the Waterfall model is fit for projects with clearly defined requirements and constraints, the following case study illustrates the effectiveness of the Scrum methodology in a dynamic environment where adaptability and iterative development are beneficial.

Background

Following the successful installation of the digital banking system at Horizon Bank, an enhancement project was initiated to expand the capabilities of the bank's mobile banking app. The project focuses on adding new functionalities, such as improved transaction processing, enhanced security features, and more user-friendly interfaces. This phase requires integrating with the newly established core banking system while ensuring a seamless user experience across platforms.

Given the flexibility needed to respond to evolving customer requirements and feedback, the Agile delivery model was chosen. Agile allows for iterative development, delivering features in small, manageable increments. This approach enables continuous testing, feedback loops, and adjustments throughout the project, ensuring the solution remains aligned with business needs and user expectations as development progresses.

Project Type and Scope

The project involves developing new functionalities for the mobile banking app, such as improved transaction processing, enhanced security features, and user-friendly interfaces. The scope is defined initially but remains flexible to accommodate changes based on user feedback throughout the development process. Essential high-level scope items include:

Iterative Phases

The project follows iterative sprints, typically lasting two weeks, allowing for continuous development and feedback:

• Initiation: The project begins with a clear vision of the desired outcomes, and critical stakeholders outline the initial backlog of features to be developed. This phase establishes priorities based on customer needs and business goals.
• Sprint planning: At the beginning of each sprint, the team selects items from the backlog to focus on during that period. Goals are set for the sprint, and tasks are divided among team members.
• Execution: Development occurs in short cycles, with teams collaborating closely to implement features. Regular stand-up meetings facilitate communication and ensure any blockers are addressed promptly. Testing is integrated within the sprints, allowing for immediate feedback on functionality.
• Review: At the end of each sprint, the team conducts a review meeting to demonstrate completed features to stakeholders. Feedback is gathered to inform the next sprint and adjust priorities as needed.
• Retrospective: After the review, the team holds a retrospective to evaluate the sprint's performance, discussing what went well, what could improve, and how to enhance teamwork and processes in future sprints.

Monitoring and Controlling

Sprint velocity and customer satisfaction are monitored throughout the project to gauge progress and adapt strategies. Real-time adjustments are made to accommodate emerging requirements or technical challenges, ensuring flexibility and responsiveness.

Closing

The project culminates in the launch of the upgraded mobile banking application, followed by training sessions for users and support staff. A post-launch review assesses the project's success based on user adoption rates, satisfaction metrics, and the achievement of initial goals.

Conclusion

This case study illustrates how the Scrum framework's iterative and adaptive approach is well-suited for projects that require flexibility and rapid delivery. By embracing Scrum, Horizon Bank effectively responds to changing customer needs and enhances its mobile banking application. The project demonstrates how Agile methodologies complement traditional Waterfall projects.