What is Spiral Model? When to Use? Advantages & Disadvantages

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Software Development life cycle (SDLC) is a process used in Project Management to undertake different stages and tasks involved in phases of writing code and deploying software. SDLC Describes the software development processes from Initial planning (Requirement) through maintenance and eventual retirement the complete application. A Goal of SDLC is too quick and efficiently produces high quality of software. The number of phases is different in SDLC will vary depending on Business and its Software Requirements usually there would be five to seven steps like software design, development, testing, releasing and maintained until it is discontinued any changes. Various Software Development Life Cycle models exist the right module depends on any given project. some of the models can be combined into hybrid models, in this day’s Documentation is crucial, regardless of the SDLC model for a given application, and the process is usually done parallel to development.
Most Important and popular SDLC models followed in the Industry are –

  • Waterfall Model.
  • Iterative Model.
  • Spiral Model.
  • V-Model.
  • Big Bang Model.
  • And Present Agile Methodologies.

The Phases involved in SDLC are- Requirements, System Design, Implication, Testing, Developing, and Maintenance, Each Phase describes-


All the customer needs and requirements of the system are captured and prepared a document in a requirement specification document.

System Design:

The requirement specification document is shared in this phase and the System design is prepared. This design helps the specifying hardware and system requirements and also helps in overall system architecture.


Here the inputs from system design are first developed into a small program called units, which are a feature integrated into the next phase. Each unit is coded and tested as unit testing.


All the units developed in the implementation stage are integrated into a small piece of the application, Post integration the entire system is tested for faults and failures of the successful application.


Once the non-functional and functional testing is done, the product is deployed in the customer environment and checks for any faults then it is released into the market.


If any issues found in the client environment to fix, these issues are fixed as patches and released, maintenance is done at customer development environment.

What is Spiral Model?

The spiral model is a combination of the Waterfall model and Iterative model which works on incremental and prototype techniques. The mostly spiral model strategy is followed by large and complicated projects where huge risks and high development and testing go in an incremental basis, Even though this model is quite old it’s still useful for large projects to finish the application quickly with development and testing which involves the client at the unit phase.

There are five stages in this Model-

  • Planning each phase and next phase.
  • Risk Analysis
  • Engineering
  • Execution
  • Evaluation

Planning each phase and the next phase:

Development of code and testing start from the planning phase and carries over until the evaluation phase, all the requirements are collected in this phase, it includes cost estimation, schedules, and resources to iteration, also understand continuous communication between system analyst and customer to have a clear note of requirement.

Risk Analysis:

in Risk analysis stage all the risk occurred during development and testing are cleared for nest irritation, where risk mitigation strategy is planned and finalized to get out from the risk involved.

Engineering & Execution:

In the engineering and execution stage we start executing the Test Cases we have identified and build with the application and deploying the software at the customer site, a reason for the success of Spiral Model is analysis and engineering are carried out in all each stage of the project.


Evaluating the software by a customer and also identifying and monitoring risks of the schedule slippage and cost overrun of the project.

When to Use the Spiral Model?

  • For large and big projects with involves heavy risks.
  • If Requirements are more complicated, unclear and complex.
  • If frequently changes required in the project and releases need frequent.
  • When the creation of the prototype is applicable in the project.

Advantages & Disadvantages of Using the Spiral Model

  • Some would consider it the best practice for developing and testing complex and large projects.
  • Cost-effective.
  • Better risk and management analysis and time management.
  • Easy and Fast Development for a quick view of progress
  • Easily we can change if any changes happen in the middle of the development stages through documentation.
  • Always space for customer feedback for a developed piece of code.


  • Difficult to handle the strategy for small projects.
  • Not useful for Low-risk Projects.
  • Need more experience resources as the process is bit complex to finish.
  • Huge and Large Documentation is required.


There are many SDLC methodologies, but there are no one size fits all solutions. Depending on your needs, especially if you’re in charge of an extremely large project, the Spiral Method of SDLC might be the one for you.

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