Different Models of Software Development Process Phases Realization
If the software development life cycle phases are common for each software build no matter the topic and peculiarities, the methodologies of their applicant could vary on many factors, which we will discuss later. Now, we assembled and explained the main 8 methodologies so you can study them and decide which model can be involved in your project creation. But it's crucial to remember that these models are not exclusive of one another, so development teams frequently combine different approaches depending on the particular requirements of the project.
Agile Model
This type of model is on the top of the methodologies list by frequency of use. Agile methodology implies a division of steps in software development cycle into cycles, each of which is obliged to make at least a small change. The development team can use the visual tools (such as Kanban boards) to track tasks and work stages.
Benefits:
- Projects are easily adapted to changes, even if the requirements change at a late stage.
- Iterative approach allows reacting quickly to feedback and new needs.
- Constant interaction with the customer allows them to better understand their needs.
- Regular deliveries of the working product (each sprint/iteration) create confidence in the customer.
- Frequent releases and demonstrations of intermediate results allow problems to be identified at an early stage.
- No «big bang effect» when the result of the project is unknown until the very end.
- Constant feedback and testing at every stage of development allows you to find and correct errors faster.
- Incremental development facilitates the management of technical debt.
- Regular meetings (such as daily stand-ups) maintain synchronization and improve collaboration.
- All project participants (developers, managers, customers) have a clear idea of the current status of the project.
- Attention is given to the most important and priority tasks, which allows minimizing unnecessary work.
- The focus on team involvement and greater autonomy increases motivation.
- The successes are noted on retrospectives, which promotes team spirit and process improvement.
Waterfall Model
Also, one of the most frequently-used types. This one is an opposite one to an Agile model. It is a linear cascade approach to project management, where each stage is performed consecutively. The waterfall model is suitable for projects where the risk of change is minimal.
Benefits:
- Easy to monitor the process and track progress by stages.
- Suitable for projects with a predictable and stable set of requirements.
- There is detailed documentation at each stage, which simplifies the control and management.
- The next step means that the previous one is complete, which simplifies reporting.
- Each stage requires the detailed documentation, which facilitates the transfer of knowledge and future system support.
- Testing starts after the development is completed, and all elements are tested simultaneously, which allows verifying the integrity of the system.
Spiral Model
To give risk analysis priority, this approach combines the linear flow of the Waterfall model with the repeating cycles of the Agile model. The spiral model is suitable for projects with a long development cycle and high complexity, where requirements can change in the process of work.
Benefits:
- The spiral model focuses on early detection and elimination. Risk analysis and minimization measures are carried out in each cycle. This is especially useful for complex projects with a high degree of uncertainty or novelty.
- The development process is divided into small cycles, which allows you to react flexibly to changes in requirements and adjust the project at any stage.
- Each iteration is completed with a working prototype that can be improved and refined.
- The project is developed in stages: first basic functions are implemented, then more complex features are added. This allows the customer and users to see intermediate results and make changes early.
- In each iteration, intermediate versions of the system can be tested. This reduces the risk of developing unnecessary or inefficient functions.
- Every cycle requires planning, which gives a clear idea of the current status of the project and the deadlines for the tasks' completion. Documentation and reports help track progress and manage changes.
- Each iteration allows correcting the errors of previous steps, improving functionality and adding new features.
Big Bang Model
With this type, developers take a novel approach and get straight into coding with little preparation. This implies that there is no defined plan and requirements are implemented as they become available. The program may need to be completely redesigned if adjustments are required. Ideal for small teams and startup projects where the scope of tasks is limited, but the requirements are well known and stable.
Benefits:
- The absence of complex phases, iterations or long-term planning facilitates project management.
- Compared to methodologies requiring detailed planning and meantime reports, Big Bang saves time and resources on documentation preparation.
- The team can react quickly to changes in requirements and implement them, as there are no strict steps and binding to intermediate results.
- The whole system is implemented immediately, which avoids long intermediate stages of integration and testing.
- The team focuses on a single goal - a finished product, not partial releases or intermediate tasks.
Incremental Model
This approach is more gradual in nature, breaking the system up into digestible increments, each of which represents a subset of the system's overall capabilities. This method develops and delivers each increment independently.
Benefits:
- You can provide a working version with limited functionality at an early stage. This is useful for feedback and adjustment of requirements.
- It is easier to make changes as the project progresses, since each new increment can include updated requirements.
- The risk of a project going out of control due to incorrect initial planning is reduced.
- Because the product is developed in parts, it is easier to track progress and make adjustments in a timely manner.
- It is possible to plan the stages in time intervals, which simplifies the management of resources and tasks.
- If a certain increment fails or is implemented unsuccessfully, you can localize and fix the problem without affecting the entire project.
- Errors and inconsistencies are identified at an early stage.
- Users or stakeholders can test intermediate versions and provide feedback, which allows better meeting their needs. This also reduces the likelihood that the final product will not meet expectations.
- Developing individual parts of the product allows the team to focus on small tasks, which makes it easier to work on complex projects.
- The gradual testing of each increment allows detecting and eliminate defects before they accumulate.
- Improvements based on previous experience of the increments are used.
Iterative Model
With this model, development cycles are repeated, allowing for input and improvement at every stage. Phases are frequently repeated until the successful completion of the final product.
Benefits:
- The project can be adjusted in the process of execution based on new requirements or changes.
- Allows for rapid response to unforeseen circumstances or change in priorities.
- At each stage the stakeholders (clients, customers) receive partial results and can make proposals.
- Early detection of errors and problems, which makes it easier to correct them.
- Even if the project is stopped, there are still useful insights that can be used in the future.
- The client sees how the project develops throughout the cycle, which increases his confidence in success.
- The risks are reduced by dividing the project into small, controlled parts.
- You can roll over or change the direction of a project if current iterations show that the chosen path is not effective.
- Continuous testing at each cycle allows product improvement based on feedback and elimination of defects.
- At the end of each iteration, a product version with higher stability and quality is created.
- Regular meetings and discussions help to maintain transparency and synchronization within the team.
- Clear assignment of tasks and control of the execution of each step.
- When requirements are not clear from the start, an iterative approach allows for a final product vision to be formed as it is developed.
Rapid Application Development
Rapid prototyping and end-user feedback are the main goals of the RAD methodology. Iterations and user input are used to quickly improve and polish the product.
Benefits:
- Projects are created with a focus on prototypes that are constantly improved based on feedback. This reduces the time from idea to implementation.
- RAD allows for easy changes at any stage of development, which is especially useful when changing requirements on the part of the customer.
- Frequent iterations and prototype testing help to quickly identify and correct errors, reducing the likelihood of major problems in the final version of the product.
- Engaging the customer and end users early on ensures that the final decision will meet business expectations and requirements.
- Teams work in parallel on different project components, which speeds up the development process and reduces the load on individual participants.
- Since errors are detected and corrected during the design process, there is less need for costly corrections at later stages of the project.
- Less focus on formal documentation reduces the bureaucratic burden and allows you to focus on development and testing.
Verification and Validation Model
Think of this as a continuation of the waterfall model, which highlights the connection between the phases of development and testing. According to this paradigm, there is a testing period for every level of development.
Benefits:
- Verification allows finding errors even at the design stage, checking compliance with requirements and specifications.
- Reduce the cost of correcting errors, as they are detected in the early stages of development.
- Validation ensures that the end product meets the needs of users and meets the expectations of the customer.
- Systematic checking reduces the chance of critical errors in release.
- The parallel use of verification and validation reduces the likelihood of a product being released with serious defects. Ensures that the product will work correctly in the real operating environment.
- Methodology facilitates clear division of tasks and responsibilities at the development stages.
- Periodic checks and milestones allow evaluating progress and quality.
- V&V can be used in combination with other approaches, such as Agile or Waterfall.
- The methodology is easily adaptable for projects of different sizes and complexity.
- Supporting the strict V&V procedures improves the reputation of the development team and builds trust among customers and users.
- The methodology helps to meet industry standards (e.g., ISO/IEC) and regulatory requirements, which is especially important for critical systems (medicine, aviation, finance, etc.).
How to Choose the Steps in Software Development Cycle Implementation Methodology
In order to choose the right development methodology depends on the project characteristics, goals and team limitations. Here are some tips how you can estimate those three factors and make a decision based on the results:
1. Evaluate the project nature
Project size: Small projects may require flexibility, while large ones may require structuring.
Complexity and novelty: If the project includes research components, iterative approaches are useful. For simpler tasks, linear ones are suitable.
Requirements and their variability: The constantly changing requirements point to the need for a flexible methodology.
2. Set a time and budget frames
If the deadlines are rigid and fixed, it makes sense to use a Waterfall or V&V model (traditional methods).
Flexible methodologies (Agile or Iterative) will work well in flexible time and budget because they allow you to adapt to changes.
3. Understand the structure of the team
Large and distributed team: It is better to choose a methodology with clear roles and rules.
Small or self-directed team: Unrestricted types will be suitable for minimizing bureaucracy and improving productivity.
4. Analyze customer engagement
If the customer wants to be actively involved and check progress often, choose cycle modal types.
With low engagement and clearly defined requirements, the linear modal types are better.
5. Test the approach in beginning
If you are in doubt, use the trial approach: apply the chosen methodology in one phase of the project and see how it fits.
6. Examples of selection depending on the project
Application for startup - Big Bang or Rapid Application model.
Project with strict regulations - Waterfall or V&V-model.
Project with high level of uncertainty - Agile or Iterative model.
