The Spiral Model

6 Mar

The Spiral Model is another model of traditional software development and has 4 stages:

1. Planning

2. Risk Analysis

3. Engineering

4. Evaluation

The system repeatedly passes through these phases in iterations called spirals.

1. Planning:

The baseline spiral is the planning phase. Here, requirements are gathered and risk is assessed. Each subsequent spirals builds on the baseline spiral.

2. Risk Analysis:

The objective of this stage is to identify possible risks and come up with alternate solutions.  A prototype is produced at the end of the risk analysis phase.

3. Engineering Phase

Software is produced in the along with testing at the end of the phase.

4. Evaluation Phase:

This allows the customer to evaluate the output of the project to date before the project continues to the next spiral.

The Spiral Model is generally used in the following circumstances:

  • When costs and risk evaluation is important
  • For medium to high-risk projects
  • Long-term project commitment unwise because of potential changes to economic priorities
  • Users are unsure of their needs
  • Requirements are complex
  • New product line
  • Significant changes are expected (research and exploration)

Advantages of the Spiral Model:

1. Provides an early indication of possible risks to the system
2. Users see the system early because of rapid prototyping tools
3. User involvement maximised – they can be involved at each stage
1. Time spent for evaluating risks too large for small or low-risk projects
2. Time spent planning, resetting objectives, doing risk analysis, and prototyping may be excessive
 3. The model is complex

2 Responses to “The Spiral Model”

  1. sad111511053 March 7, 2013 at 9:19 am #

    Very good blog. Good explanation of the 4 stages and also the advantages/disadvantages.

  2. sad112540853 March 8, 2013 at 12:58 am #

    Great blog, very clear and to the point 😀 I will be using this blog for revision for the exam 😀 Thanks 😀

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