Incremental development is a crucial element of agile methodologies that is prominently featured in the Project Management Institute – Agile Certified Practitioner (PMI-ACP) exam. This approach to software development involves breaking down a project into manageable increments or portions and then developing and delivering each increment individually over time.
Unlike a linear approach such as the waterfall model, where the entire project is delivered once, the incremental development approach allows teams to make continuous improvements throughout the life cycle of the project, accommodating changes more efficiently and effectively.
Distinguishing Incremental and Iterative Development
To understand the incremental development, it is essential to differentiate it from another common approach – iterative development. Incremental development focuses on adding new features in successive versions, each one building on the previous version. In contrast, iterative development is concerned with refining the same feature set until it attains the desired level of completeness or perfection.
| Development Type | Key Focus |
|---|---|
| Incremental | Adding new features in successive versions |
| Iterative | Refining the same feature set |
Process and Advantages of Incremental Development
In an incremental development model, each increment or phase passes through the steps of requirements, design, coding, testing, and maintenance. At the end of each phase, a fully functioning portion of the software is delivered to the customer, providing partial but immediate value.
This approach also provides various advantages:
- Risk Reduction: By delivering software in increments, errors or issues can be detected and resolved earlier, reducing the risk of project failure.
- User Feedback: Early delivery of increments allows for user feedback which can be incorporated into the subsequent increments. This contributes towards better project outcomes tailored to the users’ needs.
- Flexibility: Incremental development offers flexibility for changing requirements. The changes can be accommodated in the upcoming increments without making significant alterations to the previously developed increments.
- Reduced Costs: It limits the financial exposure of the project to the current increment being worked on. It also supports the early realization of business value since usable software is delivered at the end of each increment.
Example of Incremental Development Approach
For example, consider an online shopping application.
- In the first increment, the fundamental feature, such as browsing items, is developed and delivered.
- In the second increment, advanced features like adding items to a cart could be introduced.
- In the third increment, payment gateway integration could be developed, and so forth.
Each delivery not only brings immediate value but paves the way for improvements and advancements in future increments.
Conclusion
The incremental development approach aligns perfectly with the Agile mindset. It encourages the frequent inspection and adaptation, enabling the development team to react promptly to changes in the project environment. It is an excellent approach for teams seeking high adaptability, quick feedback loops, and a lower risk profile for software development projects.
Whether you are preparing for your PMI-ACP exam or striving for successful project completion in your organization, understanding the incremental development method and its practical application is crucial. Use this knowledge to better analyze, plan, and implement your software projects, enhancing your proficiency as a project management practitioner.
Practice Test
The incremental development approach is widely used in Agile methodologies. Is this statement true or false?
Answer: True
Explanation: Incremental development divides a system into smaller parts, which are then developed separately and implemented gradually. This technique is commonly associated with Agile methodologies like Scrum and Extreme Programming (XP).
Incremental development is an example of which of the following development approaches?
- a) Waterfall Model
- b) Spiral Model
- c) Iterative Model
- d) RAD Model
Answer: c) Iterative Model
Explanation: Incremental development falls under the iterative model, where the product is developed and delivered in parts over time, unlike the waterfall model where development follows a linear path.
The primary focus of incremental development is on software features. Is this statement true or false?
Answer: True
Explanation: In incremental development, each increment, or iteration, delivers a piece of functionality. Therefore, the focus is indeed on developing and integrating software features.
In incremental development, which of the following benefits is not true?
- a) Risk reduction
- b) Rapid delivery of useful software
- c) Higher project costs
- d) Frequent feedback and adaptation
Answer: c) Higher project costs
Explanation: Instead of escalating the costs, incremental development usually helps to control the costs. It allows changes to be made during the development process which reduces the chances of costly reworks after final delivery.
In incremental development, each increment is fully designed before beginning another one. Is this statement true or false?
Answer: False
Explanation: Unlike the waterfall model, incremental development does not require full design of each increment before starting another. Changes and adaptations are frequent in this model.
Coverage of functionality is not improved in incremental development. Is this statement true or false?
Answer: False
Explanation: Incremental development focuses on delivering slices of functionality and hence improves the coverage of functionality over time.
Which of the following is not a core principle of incremental development?
- a) Complete functionality requirement in increments
- b) Empowerment of the development team
- c) Client involvement is unnecessary
- d) Early and regular delivery
Answer: c) Client involvement is unnecessary
Explanation: In incremental development, client or stakeholder involvement is crucial to provide feedback and make necessary adjustments to the software along the development.
Incremental development results in delay of project completion. Is this statement true or false?
Answer: False
Explanation: Incremental development aims at delivering functionality early and frequently. This helps in preventing delays and ensures efficient project completion.
One of the disadvantages of the incremental development approach is:
- a) The high cost of incremental testing
- b) Difficulty in integrating increments
- c) Both a and b
- d) None of the above
Answer: c) Both a and b
Explanation: While the incremental development approach has several advantages, it does come with challenges such as the high cost of testing each increment and integrating different parts of the software.
Estimation in incremental development is more accurate than other models. Is this statement true or false?
Answer: True
Explanation: Incremental development tends to produce more accurate estimates since each increment is smaller, easier to estimate, and allows for frequent re-evaluation.
Interview Questions
What is Incremental Development in Agile methodology?
In Agile methodology, Incremental Development refers to a process where the large projects get divided into smaller modules or components. These smaller portions get developed, tested, and integrated in incremental steps.
How does Incremental Development benefit an Agile team?
Incremental Development helps Agile teams to manage complexity, reduce risks, provide value to customers early and consistently, and receive feedback which can be used to make necessary adjustments in a project.
What is the difference between Iterative and Incremental Development?
Iterative development is a process where a feature is developed and continuously improved in cycles, while Incremental Development involves completing functionalities layer by layer. Both methods together enable Agile teams to deliver working software with increasing functionality.
Define a ‘release’ in the context of Incremental Development?
A ‘release’ in the context of Incremental Development is a working version of a product which comprises numerous increments and is introduced to users or stakeholders.
What progression does an Incremental Development approach follow?
An Incremental Development approach follows a progression where the project scope is clearly defined, and then broken into smaller components or increments. Each of these increments is then developed and delivered sequentially.
How is the project scope handled in Incremental Development?
In Incremental Development, the project scope is clearly defined and understood before the project begins. The scope is then divided into smaller, manageable components that are developed and delivered in a specific sequence.
How does Incremental Development affect cost and scheduling in Agile projects?
Incremental Development makes it easier to estimate cost and scheduling as the development, testing, and integration of each increment are handled separately. This allows for better control and adjustments as necessary throughout the development process.
How does feedback impact Incremental Development?
Feedback is fundamental to Incremental Development. After each increment is released, the team collects and incorporates feedback from stakeholders and users. This continuous feedback can lead to adjustments and improvements in the subsequent increments.
What does “value delivery” mean in the context of Incremental Development?
“Value delivery” in the context of Incremental Development refers to the continuous delivery of functional and valuable components of a product to the customer. This means that value is provided consistently, not only at the end of the project.
How can Incremental Development reduce risks in Agile projects?
By dividing the project into smaller increments, the risk associated with managing large, complex projects is reduced. Moreover, the development-risk remains limited to each individual increment, and issues can be identified and resolved early on.
What is the role of a Product Owner in Incremental Development?
The Product Owner plays a major role in Incremental Development. They prioritize the increments or features that must be built, they articulate the vision of the product, and regularly interact with stakeholders to gather feedback and adjust the approach as needed.
What determines the sequence in which increments are developed in Incremental Development?
The sequence in which increments are developed in Incremental Development is typically determined by the Product Owner, based on factors such as business value, feedback from stakeholders, and the technical feasibility of implementing certain features.
How does Incremental Development contribute to the transparency in Agile projects?
Incremental Development contributes to transparency in Agile projects as stakeholders typically have a sense of progress with the delivery of each increment. It also enables teams to obtain frequent feedback, allowing for a clear understanding of project status and adjustments to be made as necessary.
How does the constant delivery of increments in Incremental Development affect the project’s quality?
Constant delivery of increments in Incremental Development contributes to maintaining high project quality as it allows for regular testing and immediate fixing of defects or issues. Regular stakeholder feedback also plays a significant role in maintaining and improving quality throughout the project timeline.
In what scenario would Incremental Development be inappropriate to use?
In a scenario where the client is unsure about the project requirements or the final product, Incremental Development might not be the best approach, as it requires a well-defined initial scope and a clear understanding of the final product’s features and functionalities.
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