Software Development Methodologies: Top 8 Models Overview
Developing high-quality and reliable software is a challenging task that demands a comprehensive and structured approach. Here comes to help the concept of the software development life cycle (SDLC).
It’s can be defined as a framework that software engineers’ team follows that enables them to develop applications meeting requirements and timeline and providing value to their users.
So, we’re going to discuss this process of software development and the various SDLC models that are employed by developers’ teams.
What is the Software Development Life Cycle?
The software development lifecycle defines and organizes the tasks necessary to complete the development of software. It is the structure and steps the development team follows on all of their projects.
Also known as the product development lifecycle, the process comprises several steps or phases that facilitate the creation of robust applications. The SDLC phases address the complexity that underlies software development and attempts to improve the process. The goal is to ensure that the final results are in line with the quality and functionality expected of the organization.
Before engaging in the defined SDLC steps, let’s discuss why software development teams need to implement and follow SDLC. As we have said before, the product development is a complex process that requires not only designing and engineering work but a lot of communication between team members.
Moreover, according to Stackoverflow developers’ survey, there are many more obstacles that impact the project. Here is all the list of the most distracting things for programmers that can affect software development productivity and quality.
Therefore, the SDLC methodologies are designed to fight almost all these challenges and make the work on the project smooth, non-distracting at all with effective communication, meetings, and management processes, and optimized workload.
So, let’s move ahead and discuss how to set the software development life cycle model and what step it should comprise to be effective.
What are the SDLC Steps?
There are six basic steps in the software development process. Each one is important in its own right, and skipping steps leaves a development team open to failure that could have easily been avoided.
Specific SDLC methodologies have different ways of implementing the steps and we will investigate them shortly. First, let’s take a closer look at the general steps that are part of all SDLC approaches.
Planning and requirement analysis
The first step in the software development life cycle is the most important in the process. It is where fundamental decisions are made regarding the feasibility of the project. The planning stage also addresses risks and quality assurance issues that may impact development.
After the planning phase of the SDLC, the team will agree on the technical approach that will be used to develop the project while minimizing risk. This step involves input from the customer, industry experts, and internal sales and marketing departments.
Defining the requirements of the project
When planning is complete we define and document the product requirements, eg. what functionality and interface it needs to have, what tech stack to choose for implementing that.
In results, we deliver a software requirement specification (SRS) that is detailing on the project sent to the customer for approval. The SRS clarifies what needs to be designed and developed during the software development process.
In the design phase of the software product development life cycle, we consider the overall architecture of the project. Here can be helpful the design document specification (DDS) is produced which often suggests multiple approaches for fulfilling the previously defined requirements.
In the DDS you can add all details on all modules designs and entire architecture.
After you have specified all the aspects of design, you are ready to move to start the design development process in the form of creating mockups, wireframes, prototypes and then moving to the interface.
This is the building phase of the application development life cycle.
The team defines and applies the most applicable programming languages, frameworks, and technologies to the product development as under the DDS.
The interesting fact is that giving the DDS and design phase adequate attention can make the development step run much more smoothly. A detailed and organized DDS paves the way for rapid and consistent module creation.
Some level of testing takes place, for sure, in all phases of the SDLC as work proceeds on the project.
At some point, a thorough evaluation of the application is required to determine how well it achieves the requirements defined in the SRS. The testing phase identifies defects and bugs that need to be addressed and may require multiple iterations to reach the desired level of quality and functionality in the finished product.
Release and maintenance
When you finish the testing and fixing phases, it’s time to release the product to the market. The application may undergo user acceptance testing (UAT) with a limited subset of users to verify that it is ready for general release.
Though the product is released, the work on it continues. Maintenance is an ongoing process throughout the life of the product as bugs or deficiencies in the software are discovered and corrected by the development team.
Here is a little bit more detailed video explaining the software development cycle and stages, if you need more information.
What are SDLC methodologies?
Well, now having an understanding of the main SDLC stages, it’s time to move ahead to the methodologies and their different types.
In a nutshell, the system development life cycle methodology is a set of repeatable processes that, when followed, present a path to successful results. These processes have proven to be valuable in helping development teams create quality software.
There are several types of SDLC methodologies, but the most popular ones are the next one under the Stackoverflow survey:
Besides, Agile popularity isn’t unpredictable as under the PwC research the Agile projects are 28% more successful than those that don't follow any approach.
Of course, implementing the methodology into your project requires time and effort but rewards in a lot of benefits for your team and product.
Benefits of using SDLC methodologies
Thus, if you still are not using the methodology for your product development, let’s explain why you should start and what advantages you get:
- Most methodologies are well-documented, making it easier for teams to adapt their processes and standards.
- Comprehensive steps are laid out to facilitate development.
- Effective development and design standards are defined.
- SDLC methodologies are more useful on large projects with buy-in from all team members.
- Prospective costs and completion time can be evaluated before starting the project.
- Precise requirements are obtained through working with the customer and obtaining approval for the software requirement specification.
- Change in team staffing can be absorbed throughout the development project.
- Maintenance is easily performed due to the modular nature of the processes used to complete the application.
Potential disadvantages of an SLDC methodology
- Some methodologies are only effective for projects of a certain size.
- It can be difficult to estimate costs and overruns when initiating the project.
- Requirement changes are hard to implement once development is underway.
- The time and cost of completing a project may increase with certain development methodologies.
- Project definition needs to be completed before development can start.
- It may be difficult to obtain customer input after the initial steps of systems development are complete.
Hopefully, after these, you know that selecting the right methodology can have a dramatic impact on the success or failure of a given project. There are many different types of methodologies from which to choose.
Let’s look at some of the choices you have when considering the types of development strategies to use in a software development project.
Popular SDLC Methodologies
Here is an overview of some of the SDLC methodology options available to development teams. We will highlight some of the pros and cons of each methodology.
Waterfall SDLC Model
The Waterfall model is one of the earliest ones, having appeared in the 1950s and defined in the 1970s by Winston W. Royce. Waterfall software development is characterized by a very straightforward approach that follows a rigid series of steps. Each phase is required to be completed one by one and there is no going back to a previous step.
- Easy to manage due to well-defined starting and endpoints for each step
- High-degree of accuracy surrounding cost estimates
- Clearly defined requirements and outcomes
- Technical documentation is created during initial requirement gathering
- Test scenarios are defined in functional specifications
- Slow delivery speed compared to other methodologies
- Inflexibility regarding changes to initial requirements
- Difficulty in defining the functional specifications of client requirements
- Not suitable for large projects
The V-Model builds on the foundation of the Waterfall model that includes a testing phase associated with each development stage. It is also known as the validation and verification model. The V-Model is one of the most inflexible yet thorough of the various SDLC testing methodologies. Each phase of the model must be successfully completed before the next one begins.
- Identifies defects early in the development process
- High success rate
- Simple to understand and easy to implement
- Saves time by incorporating planning for testing before coding begins
- Extremely rigid and inflexible
- Early prototype creation is impossible
- Updating test and requirement documents to reflect changes can take time
The Iterative model builds on an initial set of software requirements and through testing and evaluation identifies further needs. Each iteration of the development process produces a better version of the product.
Requirements are defined as the process is repeated and problems with prior versions of the software are resolved. There is no pre-defined number of iterations when a project commences, as it is understood that the model will be followed until a satisfactory outcome is achieved.
- Easily adaptable to changes in client and project requirements
- Functional and design flaws are identified early in the development process
- Streamlined management of individual iterations
- Optimizes limited financial and time resources
- Design issues related to incomplete initial requirements may occur
- Not suitable for small projects
- May require additional, highly-skilled human resources
The Spiral methodology is one of the most flexible options and is usually employed in large-scale projects. It allows highly customized products to come out of the software development efforts.
The model repeats the four phases of planning, risk analysis, engineering, and evaluation until the product is fully refined and finished. Each iteration of the four phases starts with an attempt to identify development risks and the best ways to avoid them.
- New functionality can be introduced later in the development process
- Enhanced risk management
- Cost estimation is facilitated by the incremental nature of the model
- Fast development and an emphasis on customer feedback
- Requires expertise in risk management
- Difficulty meeting financial budgets or delivery schedules
- Additional documentation due to the required intermediate phases
The Agile model is based on an incremental and iterative approach to software development. As a concept, the Agile model has been adopted by businesses for non-software related activities, but now it is widely used in the software industry.
It produces many consecutive product releases that contain incremental improvements to the previous versions of the application. Each iteration of the product is thoroughly tested before the project proceeds. To be effective this model requires setting up an Agile team with specific members.
- No budgetary constraints to introducing new requirements
- Fully engages business stakeholders in the development process
- Lessened documentation requirements save time and money
- Small issues are identified before they become major problems
- Hard to estimate the effort required to complete complex projects
- Requires experienced resources
- High failure risk when end-user requirements are vague
The Lean model is similar to agile development with its focus on speed of delivery and continuous improvement throughout the project. It focuses on the Lean principles that include eliminating waste, empowering the team, delivering as fast as possible, and making decisions as late as possible. These characteristics have made the Lean model popular in many areas of the business outside of software development.
Delivers increased functionality in a reduced timeframe
Eliminating unnecessary activity saves time and money
Enables fast decision making and is easily scalable
Requires excellent documentation for cross-team communication
A dependence on the team makes it easy to lose focus
DevOps model is one of the newer SDLC models and is a must-have for any project. As it involves the melding of the development and operation teams of an organization. The goal is to streamline product delivery and support while minimizing organizational risks. This model takes a more holistic approach to software development and maintenance.
- Changes in requirements can be implemented quickly
- Operational input results in easier to manage software
- Demands the elimination of organizational silos
- Requires team members with multiple skillsets
Big Bang Model
This model concentrates on the development portion of the process. It neglects most of the formal requirement definition that is part of many other models. This process is often called upon to address emergencies that demand rapid development.
- Quick turnaround time for project completion
- Ability to respond to changing requirements
- Lack of initially defined requirements
- Relatively high risk of failure
The rationale behind the concept of the software development life cycle and its variety of incarnations is to make it easier for developers to successfully create quality software products. Depending on the scope of a particular project, it may make more sense to use a specific SDLC model.
Things to consider when choosing a model include the financial, human, and technical resources available for the project. Time constraints may impact the decisions as some models enable a faster turnaround. This overview should serve as a good starting place from which to find the right methodology for your team.
Though if you still hesitate on implementing one or another model, get a free quote on the project management from our PM experts and we figure out the best approach for your case. And keep in mind, finding the right model will make it much more likely that your development goals succeed.