Advantages/Disadvantages of the Spiral Model

3 Mar

There are a number of advantages and disadvantages with regards to the spiral model. The spiral model is a traditional agile model which contains 4 different stages:Planning, Risk Analysis, Engineering and Evaluation. Software projects are constantly passing through phases in iterations,in other words spirals. The baseline spiral, starting in the planning phase, requirements are gathered and risk is assessed. Each subsequent spirals builds on the baseline spiral.

diagram of Spiral model:

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.
  • Project estimates in terms of schedule, cost etc become more and more realistic as the project moves forward and loops in spiral get completed. 
  •  It is suitable for high risk projects, where business needs may be unstable.
     A highly customized product can be developed using this.

 

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.
  • It is not suitable for low risk projects.
  • May be hard to define objective, verifiable milestones.
  • Spiral may continue indefinitely.

Overall, I feel that the advantages of the agile spiral model outweigh the disadvantages. This agile method is safer than the older ways of implementing IS projects eg. the Waterfall model. Unlike other models, at every stage risk analysis is performed… The Spiral Model works by building progressively more complete versions of the software by starting at the center of the spiral and working outwards. With each loop of the spiral, the customer evaluates the work and suggestions are made for its modification. As a result, the customer is  constantly communicating with the specialist’s, who in turn make changes to the system based on the customers demand. This leads to an increase in customer satisfaction as customer’s can can now interact and control they’re information system’s.

Resources:

http://www.ianswer4u.com/2011/12/spiral-model-advantages-and.html#axzz2MQqbAKZZ

http://istqbexamcertification.com/what-is-spiral-model-advantages-disadvantages-and-when-to-use-it/#.UTKZtjAvnUY

http://courses.cs.vt.edu/csonline/SE/Lessons/Spiral/index.html

http://cathaldoyle.com/lecture-8-spiral-model/

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