Difference between Prototype Model and Spiral Model

A risk-driven model of the software development process is the spiral model. The spiral model directs a team to adopt components of one or more process models, such as incremental, waterfall, or evolutionary prototyping, based on the specific risk patterns of a given project. The client reviews the progress at the conclusion of each phase in the spiral model, which starts with a design goal.

What are the Requirements of the Spiral Model?

The following situations call for the employment of the spiral model:

• Whenever the software demands ongoing risk analysis or evaluation.
• If the project is enormous.
• The project’s requirements are intricate and need to be continually clarified.
• In the event that frequent releases are required.
• When software changes significantly.
• When the amount of time needed to gather and analyse end-user experience is excessive.

What is the Spiral Model?

The Spiral Model is a software development life cycle model that is highly used for risk-driven models. Based on the risk patterns of a given project, the spiral model helps developers increase the efficiency of the model as most risks are already handled. It consists of a number of loops that form a spiral shape each loop is called the phase of the software development cycle.

Phases of a Spiral Model

• Planning Phase: The needs are gathered, and examined, and the requisite resources and working conditions are identified during this phase. System requirement specifications and business need documents will be the output.

• Risk Evaluation: This stage focuses on analysing risk and potential remedies and after that the risk strategy is created and polished.

• Engineering Phase: This phase involves testing and development as the actual product is created. The engineering phase’s output will consist of things like source code, design documentation, test cases, test summaries, defect reports, etc.

• Evaluation Phase: The customer is involved in this stage. The product is assessed by the customer, who makes sure it satisfies all the requirements. Before releasing a product, it is typically vital to collect user feedback.

Basic Definition of Prototype Model and Spiral Model

1. Prototype Model: The prototype model is a software development life cycle model which is used when the customer is not known completely about how the end product should be and its requirements. So in this model, a prototype of the end product is first developed by the developers and then tested and changes were made as per customer feedback until the customer is satisfied with the prototype. 
2. Spiral Model: Spiral Model is a software development life cycle model which is highly used for risk-driven models. Based on the risk patterns of a given project, the spiral model helps developers to increase the efficiency of the model as most risks are already handled. It consists of a number of loops which are forming a spiral shape where each loop is called the phase of the software development cycle. 

Spiral Model vs Prototype Model

Prototype Model	Spiral Model
A prototype model is a software development model in which a prototype is built, tested, and then refined as per customer needs.	The spiral model is a risk-driven software development model and is made with features of incremental, waterfall, or evolutionary prototyping models.
It is also referred to as a rapid or closed-ended prototype.	It is also referred to as a meta model.
Phases: Requirements Quick Design Build Prototype User Evaluation Refining Prototype Implement and Maintain	Phases: Planning Phase Risk Analysis Phase Engineering Phase Evaluation Phase
It does not emphasize risk analysis.	It takes special care about risk analysis and an alternative solution is undertaken.
In the prototype model, customer interaction is continuous until the final prototype is approved.	In the spiral model, there is no continuous customer interaction.
It is best suited when the requirement of the client is not clear and is supposed to be changed.	It is best suited when the customer requirements are clear.
Cost-effective quality improvement is very much possible.	Cost-effective quality improvement is not possible.
In the Prototype model, improvement of quality does not increase the cost of the product.	In the Spiral model, improvement of quality can increase the cost of the product.
Large-scale project is maintained.	Low to medium project size is maintained.
When to use- When end users need to have high interaction like in online platforms and web interfaces.  Whenever end-user input in terms of feedback on the system is required.	When to use- Continuous risk analysis is required for the software In large projects If Significant changes are required by the software In complex project requirements
Advantages End users are highly involved in the whole development process. Errors, complexities get easily identified Modifications can be done with ease Continuous user feedback ensures proper and intended functioning of the prototype Users have better idea about their product	Advantages Fast development Development of all phases is carried out in controlled manner Customer feedback is taken into account for the modifications to be done accordingly incase required Suitable for large projects Suitable for risky projects Continuous risk analysis helps in better development Useful in rapidly changing requirements
Disadvantages Incomplete problem analysis Continuous involvement of user may lead to increase in complexity	Disadvantages Not suitable for smaller projects because of the high cost associated with the development process Requirement of the competent risk analysis team High possibility of not meeting the set budget or time limit.

FAQ’s on Prototype Model and Spiral Model

Q.1: What are the key features of the Spiral Model?

The key features include iterative development, risk assessment, flexibility in accommodating changes, and the ability to balance project control and flexibility.

Q.2: What are the advantages of the Spiral Model?

Advantages include risk reduction, early identification of issues, adaptability to changes, and the ability to incorporate user feedback and changing requirements.

Q.3: What are the limitations of the Spiral Model?

Limitations include complexity, potential for extended timelines, higher cost due to repeated iterations, and the need for experienced personnel to manage risks effectively.