Spiral Model

spiral model

The spiral model is one of the most prominent Software Development Life Cycle models for risk management. It resembles a spiral with several loops in diagrammatic depiction. The spiral’s exact number of loops is unclear, and it varies from project to project. 

A Phase of the software development process is defined as each loop of the spiral. Depending on the project risks, the project manager might change the number of phases required to build the product. The project manager plays an essential role in developing a product utilising the spiral model since the number of phases is dynamically determined by the project manager.

The spiral’s radius at any point symbolises the project’s expenses (cost) thus far, while the angular dimension represents the current phase’s progress. 

The phases of the Spiral Model are depicted in the diagram below: – 

As illustrated in the diagram above, each phase of the Spiral Model is divided into four quadrants. 

These four quadrants’ functions are detailed further below

1. Identifying different options and determining objectives

At the outset of each step, customers’ requirements are gathered, and objectives are identified, elaborated, and analysed. Then, in this quadrant, alternative solutions for the phase are given. 

2. Risks must be identified and resolved 

In the second quadrant, all viable solutions are reviewed in order to choose the optimal one. The risks connected with that solution are then identified, and the risks are mitigated using the best technique possible. The Prototype is made at the end of this quadrant for the finest potential solution.

3. Develop the product’s next version 

The features that have been found are created and tested in the third quadrant. The next edition of the software is available at the end of the third quadrant. 

4. Review and make plans for the following phase

Customers evaluate the software that has been built thus far in the fourth quadrant. Finally, the planning for the following step begins.

Spiral Model Risk Management 

Any adversity that could jeopardise the effective execution of a software project is referred to as a risk. The spiral model’s most essential aspect is how it handles unforeseen hazards once the project has begun. The development of a prototype makes such risk resolutions easier. The spiral approach facilitates risk management by allowing for the creation of a prototype at each stage of software development.

The Prototyping Model also enables risk management, although hazards must be fully identified before the project’s development activity begins. However, in real life, project risk may arise after development work has begun; in this scenario, the Prototyping Model cannot be used. The product’s features are evaluated and examined in each phase of the Spiral Model, and the risks at that moment in time are identified and resolved through prototyping. As a result, this paradigm is far more adaptable than other SDLC models.

Why is the Spiral Model termed the Meta Model? 

Because it encompasses all other SDLC models, the Spiral model is referred to as a Meta-Model. The Iterative Waterfall Model, for example, is represented by a single loop spiral. The spiral model integrates the Classical Waterfall Model’s progressive technique. The spiral model employs the Prototyping Model’s risk-handling technique of developing a prototype at the start of each phase. The spiral model can also be seen as supporting the evolutionary model, as the spiral’s iterations can be thought of as evolutionary layers upon which the entire system is formed.

Spiral Model Benefits

The Spiral Model has a number of benefits. 

  1. Risk Handling: For projects with a large number of unknown risks that arise as development progresses, the Spiral Model is the best development model to use because it includes risk analysis and risk management at each stage. 
  2. Large-scale projects: The Spiral Model is suitable for large and complex projects. 
  3. Flexibility in Requirements: Using this methodology, change requests in the Requirements at a later stage can be accurately integrated. 
  4. Customer Satisfaction: Customers can monitor the product’s progress early in the software development process, and as a result, they become familiar with the system by using it before the final product is completed.

Spiral Model Disadvantages

The spiral model has several major drawbacks. 

  1. Complex: The Spiral Model is significantly more complicated than other SDLC models. 
  2. Expensive: Due to its high cost, the Spiral Model is not appropriate for minor projects. 
  3. Too much reliance on Risk Analysis: The project’s successful completion is heavily reliant on Risk Analysis. The development of a project employing this strategy will be a failure without a large number of highly experienced professionals. 
  4. Time management is challenging: Since the number of stages is unknown at the outset of the project. This makes time estimation problematic.


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