Why to Adopt SDLC vs Agile Development Life Cycle for Your Project?

Software has changed the world in the last couple of decades and when we talk about Information Technology, Tech organizations, and Tech enthusiasts around the world are indulging in innovating new software and programs time and again.

It is a fact that the success of any software solution depends on the methodology and the quality of efforts invested in the development process.

Before software development models were introduced into IT organizations, the development process was often ambiguous and inefficient, producing inconsistent and unpredictable results.

The use of standardized frameworks and models helped reduce the mismatch in product expectations and delivered prototypes.

What is Software Development Methodology?

A software development methodology is broadly a framework that is utilized by the software development team, that enables them to design and develop various kinds of software applications while keeping a tab on requirement analysis, meeting budget while containing risk, and providing value to their customers.

Software methodologies are defined to ensure the software development work remains smooth, and non-distracting for the developers, with a proven standard operation procedure, effective communication, regular meetings, and an optimized workload.

In a nutshell, we can also say that a software development methodology is a group of repeatable processes that should be followed by software development organizations/developers to achieve successful results.

These processes create the foundation for a successful project and have proven to be helpful in the development of quality software.

The two most popular software development methodologies are Waterfall (SDLC) and Agile. Both are commonly used for the development of software projects and project management as well.

Though we will discuss in detail the difference between both approaches, the most common difference between SDLC and Agile is that SDLC is a sequential approach whereas Agile is iterative in nature.

What is SDLC?

Software Development Life Cycle (SDLC) is a process that helps us develop software with the lowest cost and highest quality in the shortest time possible.

SDLC offers a well-structured flow of different phases, which helps an organization to develop software in a well-structured way, and it also helps to maintain the quality, while carrying out testing and validation of the user specifications, before putting the software into a live environment.

SDLC is also known as an Application Development Life Cycle, it can be applied to the development of both hardware or software components or configuration to define its scope and life cycle process.

SDLC model is an amalgamation of both iterative and incremental process models and has a better focus on customer satisfaction and process adaptability by ensuring quick delivery of a workable software solution.

 

Requirement Gathering and Analysis 

This is the first phase of SDLC, in which it is determined that we really need some software or application to solve any kind of problem. In this phase, the requirements are assessed, inputs are taken from all stakeholders, and the shortcomings of the current system and the strength and pitfalls of the proposed system is discussed and documented accordingly.

In this stage, a Project Manager and a Business Analyst schedule meetings with the Customer, to gather all the information like the customer’s needs, expectations, process flows, the value expected, and the purpose of the product.

It is important to have a core understanding of the product before initiating the second phase of SDLC.

Design 

In this phase, we use the output of the initial phase, the SRS document (Software Requirement Specification) as input and derive a software architecture that will be used for implementing system development. 

This phase also helps in identifying and specifying the system and hardware requirements and helps in defining the overall programming language framework, database architecture, and system architecture.

The system design specifications are used as input for the next phase of the model.

Implementation/Coding 

This Implementation/coding phase starts once the software developer team gets an adequate Design document. Upon receiving the system design document, the Project Manager divides the work into small modules/units, and actual coding work is started.

This one certainly is the most crucial and longest phase of the SDLC life cycle. In this phase, the Software design is translated into the source code, and all the components of the software system are implemented in this phase only.

Testing 

Once the software code is developed, it is necessary to test it against the specified requirements, to ensure if the developed code is fulfilling the requirements defined in the first phase or not.

In this phase, every kind of functional testing like integration testing, system testing, unit testing, and acceptance testing are performed along with several kinds of non-functional testing.

Deployment 

Once the quality testing is completed, the product is delivered or deployed at the customer’s end. It could be an executable file installed at the customer’s premises or could be an application hosted on Cloud to ensure seamless access to the customer remotely.

Maintenance 

Once the software is deployed, it is required to provide adequate support and maintenance procedures to ensure it runs without any issues, and to enhance the end-user experience.

This phase gives us an opportunity to counter the problems, develop the knowledge base, and execute the regular maintenance work like software up-gradation, patching, etc.

Advantages of SDLC Model

• It is one of the easiest, most commonly used, and most manageable models.
• Because of its nature, each phase has its own deliverables and review process in place.
• It works well for small-Middle-sized projects, where requirements are well-defined and understandable.
• It offers a 2-way (forward & backward) implementation and planning approach.
• Process and results are well documented.
• In SDLC, the Process, tasks, and results are well documented.
• The Software Requirement Specification document gives enough nitty-gritty to the Software testers to design and simulate the test cases and test scenarios during the Software testing phase. It makes the testing process much easier and more transparent in SDLC methodology.

Limitations of SDLC Model

• It is not an ideal model for a large size, complex and ongoing project.
• If the requirement is not clear at the beginning, it is a less effective method.
• Very difficult to move back to make changes in the previous phases.
• The testing process starts once development is over. Hence, it has a high chance of bugs being found later in development where they are expensive to fix.
• This model does not offer much room for change, even if it is observed during the development phase.
• It often delays testing until after completion, which makes large revisions costly.
• We have a High risk and Uncertainty, due to unnoticed issues until the project is in the final phase.

What is Agile Methodology?

The agile development life cycle is driven by customer descriptions of what is required & recognizes that plans are short-lived. Agile is an iterative and incremental methodology and it has all the SDLC activities, but they are not necessarily performed in a sequential manner.

Software products are built incrementally, and each iteration will include SDLC activities. The specific structure depends on the methodology or process framework used.

The agile model believes that every project needs to be handled differently and the existing methods need to be tailored to best suit the project requirements. In Agile, the tasks are divided into time boxes (small time frames) to deliver specific features for a release.

Agile is an iterative and incremental software development approach. In Agile, the products are delivered in fixed-term time intervals by a cross-functional self-managed team.

The agile methodology could be implemented in the various kind of software development models:

• Extreme programming
• Scrum
• Extreme Programming
• Rational Unified Process

These models share a common vision, well documented in the Agile Manifesto as 12 principles. These are primarily focused on strong collaboration, continuous communication, and a rapid software development process.

Agile System Development Life Cycle Stages

Project Initiation 

This is the first phase which is also called the envision or inception phase. This stage involves important activities like project vision discussion and Return of Investment justification.

This is indeed a high-level feasibility assessment procedure where we do not delve much into the details. We do identify the team members and allocate them to work according to the time and resource availability.

This stage also covers the economic feasibility study for project approval.

Planning 

This is a speculative phase, where the Agile lifecycle kicks in. The software development team engages with the Project Sponsor, and product owner and carved out a plan for Release, they also identify the exact product they are looking for.

It is discussed how the project will be developed, and how the development will be executed by making the stories. Stories are created based on the user’s requirements, which describe the user’s vision of the product and feature, along with the utility of those features.

The teams discuss the business opportunities and the wider context of the product being assessed in this phase, which gives feedback about the functional and financial viability of the project. At the same time, Project risk and Project milestones are estimated in this phase.

We also plan the business value generated by the product and prioritize the items based on their dependencies and proposed business value.

Development 

Once we gather the requirements from all the stakeholders and the product owners then we start the development work. The Agile product development methodology helps us deliver software products in incremental phases, iterations, or sprints.

Developers start coding the first iteration of the product with the objective of developing a workable product at the end of the sprint. This is certainly not a fully functional product, and it is far from the final version as it undergoes numerous revisions to offer the required functionality.

The good thing is, that we can enhance this functionality in future iterations of the Agile lifecycle. Once we have enough sprints needed to develop a minimal viable product (MVP) to a fully functioning solution, we can release it into a production environment.

We also conduct the software testing in several iterations; however, we must perform the final testing and acceptance with the help of a QA/Software tester to detect the bugs and get them fixed.

The developer also must ensure that we have adequate training to be imparted to the support staff and end-users before the deployment of the software solution into the production environment.

Production

Once the product is put into the production environment; it is being used by the end-users and it gives an opportunity to take the feedback. It is very important to monitor the software product to identify defects or bugs in testing.

Here the production and support teams work in tandem, and proper handover and training are provided to the support and production teams, though it depends on the type of product.

This production stage ends when the software project is ready for retirement.

Retirement

It is the final stage of the Agile lifecycle. It kicks in when a software product reaches the ‘end of life’ stage, and it is decided to pull it off from the production environment and decommissioned, which is also called ‘sunsetting’.

It is an important stage as Customers must be informed about the changes and any sort of migration to the newer product and releases, or any alternative options.

Products could be retired for multiple reasons, it could be the end of life of a product or could be a deployment of a new release with technological advancements.

A software product can be retired due to a lack of feasibility and cost-effectiveness in the current business paradigm.

Advantages of the Agile Model

• Agile puts more focus on the Client, and it ensures a regular engagement of the client during all the stages of software development.
• It provides matchless adaptability abilities, which are indeed a measure of the response to any change. Agile is highly flexible when it comes to adapting to the changes requested by the client.
• In Agile, the development teams are highly motivated and well-organized, hence it is prone to produce better results from the development projects.
• Agile methodology helps to enhance the quality of software development.
• Agile is based on incremental progress, hence it offers clear visibility to the development team and the Client to assess and observe the progress of a project. It in turn reduces the development process risks.
• Agile offers a greater level of transparency, as it allows an opportunity for both the team and the stakeholders to know what is happening. The Customer can all see the periodic progression of software development, which indeed enhances the customer experience and satisfaction level.
• As we build frequent builds in Agile, it offers the capability to detect any sort of deviation from the expectations and requirements of the customer, and that can be fixed at an early stage.

Limitations of the Agile Model

• In this methodology, all the tea members should be very well-versed in Agile concepts. It requires a lot of commitment and discipline to practice Agile.
• We need an Expert/Subject Matter Expert to take important decisions.
• The Agile software development cost is marginally higher than the other development models
• If the Project Manager is not certain about the outcomes he is expecting, the project can easily go off track.
• The project documentation in Agile is less detailed, as Agile methods focused on developing working software instead of maintaining comprehensive documentation.
• It has lacked a defined structure if we compare it with SDLC. Agile demands a highly proficient, cross-trained, and self-starter team, without that the project could be in jeopardy.
• Due to frequent re-prioritization of deliverables, sometimes it is unpredictable to know what will be delivered at the end of a specific sprint.

Read More- Guide for Custom Software Development for Your Product Idea

Does it make a difference if you work with an onshore or offshore company?

SDLC & Agile development is a methodology whereas SDLC is a process used in the area of project management to carry out the process of the Software Development Life Cycle.

An offshore development company can provide SDLC and Agile development services to businesses looking to outsource their software development projects to a team of qualified professionals overseas.

As the famous quote goes “A fool with a plan can beat a genius with no plan” and adopting the best framework and methodology which is essential for the success of your project.

SDLC vs Agile – Key Difference that Matters Most

Differences	SDLC	Agile
Methodology	SDLC is a Sequential Software Development Life Cycle Model because it carries out all the activities in sequential order. The Development team can move to the next phase only once the previous phase is completed successfully.	Agile is in fact a practice, which helps us to carry out continuous iterations of software development and testing process. The software development and testing activities here are concurrent and it allows better communication among the developers, teams, managers, clients, and consultants.
Delivery	SDLC works on the principle of one-time massive whole delivery, where the complete project is delivered at the end of SDLC lifecycle.	Agile offers the flexibility to break the project into multiple small chunks of deliveries at a defined time interval. It delivers an MVP (Minimum Viable Product) at the end of each sprint.
Product Quality	SDLC is known for adequate processes and framework which helps us deliver good quality products in an efficient manner.	Agile uses an incremental development approach to incorporate and maintain software product quality.
Approach	SDLC model is based on a predictive approach for software development.	Agile is modeled on an adaptive approach to developing software projects.
Stages	SDLC divides the software development lifecycle process into different stages.	Agile divides the software development lifecycle into sprints.
Understanding	SDLC is easy to understand and follow. All the activities are well defined and divided into stages. It makes it easy to understand the project at a glance.	Agile is also a very simple approach and it is quite easy to understand. It has a well-defined structure that can help anyone to understand the project easily.
Release	SDLC offers a single cycle and single release approach.	Agile provides an approach of a repetitive number of iterations and multiple releases.
Product Support	SDLC can support any kind of software application development, which could be a small app or could be enterprise-level as well.	Agile could also be used to support any kind of software product by splitting into incremental builds.
Project Division	In SDLA, the process is considered as a single entity, which is further divided into different phases.	In Agile, the entire Software product is divided into multiple small projects and each project further has an iteration of stages.
Type of Model	SDLC is a well-structured and kind of rigid model. Once the lifecycle is started, it is quite difficult to make any alteration in the Project’s scope, description, design, and specification.	Agile is famous for the flexibility it offers. It allows making any number of changes at any stage of the project.
Planning Scale	SDLC offers a Long-term planning scale for software product development.	Agile offers a Short-term planning scale for software development.
Customer Interaction	It is one of the biggest disadvantages of SDLC, where long distance exists between the customer and the developer.	Agile scores here massively, as it offers a short distance between the developer and the customer.
Specification vs Implementation	Here we must spend a long time between the requirement specification and the final implementation. The business analyst or the Project Manager prepares the requirement before the beginning of the project, however, there could be a mismatch in the specification and the Implementation, due to the extensive time elapsed between both phases.	Here Agile offers amazing flexibility, as there is a small time between specification gathering and implementation. The product owner prepares the requirements and updates to the team in each sprint, which ensures a good match between requirements and implementation of the software product.
Testing	In SDLC, the testing phase is initiated only once the development phase is completed successfully. The planning for the testing is carried out just once before the initiation of the Testing stage. The biggest disadvantage is, the Test plan is hardly reviewed during the project, and that makes it difficult to accept any proposed changes in the Software requirements. Test cases are developed at once for all the modules and functions. Acceptance testing is done by the client only after the release. In SDLC, there is a well-defined separation between the Software development and testing teams, and there is formal and strict communication between them. In SDLC, preparing the Test documentation, Test estimates, and assignments are performed by the Test manager.	In Agile, the Testing starts right with the development phase. Testing planning is carried out before the project starts and any changes in the plan can be incorporated during the project development as well. We can review the Test plan after every sprint and make the necessary changes if required. Here the Testing team actively engages in the requirement gathering process and requirement amendment process. Here test cases could be developed in every sprint based on the functionalities and that can be released in each sprint. Acceptance testing can be performed after an iteration and just before the product delivery by either the Test team or the Business analyst. Further testing is performed at the customer’s premises after every release. The Development and Testing team are integrated as a single team and there is open and fluid communication between them. The testing team creates the Test documentation, but it is not detailed and contains only necessary information. Preparing Test documentation, Test estimates and assignments are indeed a shared responsibility of the entire team along with the actual test engineers who are engaged in assigning the tasks and providing the test estimates.
Customer Involvement	In SDLC, the customer is engaged only at the requirement gathering stage, past that there is either no or rare constructive engagement of the customer. The customer again comes into the scenario at the time of project delivery.  It sometimes negatively impacts the project as there are lesser chances of getting customer feedback during the development phase, which makes things be difficult at a later stage, which may cause rework and cost escalation.	Agile is known for its transparency and frequent Customer engagement. Here the customer is involved throughout the project, it helps the team to take the customer feedback in real-time and to work on them and do a course correction, without escalating the costs and rework concerns. It also increases customer satisfaction and faith.
Decision Making	In the SDLC model, decision-making is hierarchical and formal in nature. The project manager is the decision-maker here.	In the Agile model, decision-making is Informal. The entire team takes the decision and act accordingly.
Project Risk	In SDLC, we are prone to have higher project schedule risk.	Agile offers comparatively lower project schedule risk.
Project Requirements	SDLC is highly suitable for those projects, where we have clearly defined requirements and not many changes are expected.	Agile is the first preference for projects which are evolving and have dynamic user requirements.
Project Progress	Here we need to create manual documents, and those could be used to verify and validate the status of the Team/individual’s progress along with the direction of the project.	Agile follows the Burn Down chart and Kanban chart to validate and verify the progress of the Individual/Team and the Project.
Rework Cost	As the SDLC model is rigid and any changes require more rework, the Rework cost is very high.	Agile offers flexibility on this front and rework could be done at any point in time, which reduces the rework cost up to a great extent.

Conclusion

In this article, we explained the differences between the SDLC and the Agile approach to software development. We have presented the difference in both methodologies in a tabular form, which will give a better insight into both approaches.

So, it does not matter whether you are considering the selection for an Android app or iPhone app, or simple website development above explanation and article stands well for all type of your business needs. 

There is no doubt that choosing the right kind of methodology for developing a software product could bear substantial benefits to an organization. It is always advisable to have your software development process adapted to the custom needs of an organization.

This is where Agile scores big, as it aims at delivering rapid solutions, which can enhance productivity and customer experience by fulfilling their requirements. Agile is best considered for startups, as it offers quick development and a high level of flexibility.

Startups love Agile and it offers them avenues to utilize limited resources in an effective way to get a competitive advantage they need to sustain.

There is no doubt that currently, Agile is the most used software development methodology in the World. Agile could be used in small-medium-sized project development, whereas the traditional SDLC is still better adapted for enterprise-level projects.

Software development organizations should take decisions based on their desired Software development methodology.

The size of the team, size, and complexity of the software, geographical situation, business strategy, engineering capability, and several other aspects depends on the software development methodology we choose.

It is extremely important to conduct a thorough study to identify the differences in approach, pros, and cons of each methodology before taking the right decision.

It is also important to study the industry requirement, business strategy, and business context before choosing the correct software development methodology. 

We are pretty much sure that by pondering on the different factors provided in this article, we will be able to make an informed decision to select the right software development life cycle model to develop the software application.

We can also opt for other available methodologies like Spiral, Prototype, and V and V, but it all depends on the kind of requirement we have in place.