What is Spiral model and what is advantage and disadvantage of this model?

What is Spiral model?

  • Spiral model is a combination of sequential and prototype model.
  • This model is best used for large projects which involves continuous enhancements.
Spiral Model design and flow-

The spiral model has four phases.

  1. Planning phase
  2. Risk analysis phase
  3. Engineering phase
  4. Evaluation phase.

1. Planning Phase:

  • Requirements are gathered and analysis.
  • Doing feasibility study
  • Developed the Requirements like ‘BRS’ that is ‘Business Requirement Specifications’ and ‘SRS’ that is ‘System Requirement specifications’.

2. Risk Analysis:

  • To identify risk and alternate solutions.
  • If any risk is found during the risk analysis then alternate solutions are suggested and implemented.

3. Engineering Phase:

  • Development and testing of the software takes place in this phase.

4. Evaluation phase:

  • Customers evaluate the software and provide their feedback and approval


Advantages of Spiral model:

  • High amount of risk analysis hence, avoidance of Risk is enhanced.
  • Good for large and mission-critical projects.
  • Strong approval and documentation control.
  • Additional Functionality can be added at a later date.
  • Software is produced early in the software life cycle.

Disadvantages of Spiral model:

  • Can be a costly model to use.
  • Risk analysis requires highly specific expertise.
  • Project’s success is highly dependent on the risk analysis phase.
  • Doesn’t work well for smaller projects.