Iterative Software Development Model explained with phases

Iterative software development has demonstrated itself as a time-honored methodology of producing and refining a quality product. Understanding how to harness the power of this process can help a development team consistently generate high-quality software, particularly for large projects.

Iterative Software Development Model
Iterative Software Development Model

Introduction to Iterative Software Development

Developers have been experimenting with iterative design processes for generations, with some of the first notable examples surfacing in the 1950s. This repetitious, cyclical methodology provides developers with the opportunity to plan, design, test, and refine software until it reaches a polished state.

Breaking Down the Phases of Iterative Software Development

Iterative development provides designers with opportunities for refinement and evaluation, and does not necessitate the comprehensive development of the entire code at once. To get a closer look, here is a brief overview of the stages of iterative development. 

Plan & Design

  • For a large-scale project, iterative development allows for piecewise design, whether building a skeletal outline and adding the details during later iterations or designing completed individual pieces of the product in each iteration. 
  • Both methods are viable, depending on the nature of the project. 


  • Typically, the method of development relies on the specific iteration. 
  • For instance, a first iteration may involve more structural development, while later iterations following evaluation and refinement designs may be more detail-oriented. 

Evaluate & Analyze

  • The testing phase of iterative development is critical, although it is often undervalued or treated as an afterthought. 
  • It is this stage upon which the cyclical nature of this methodology hinges. A thorough functional analysis of the current iteration will determine the foundation nature of the following iteration. 


  • Good refinement requires being realistic. 
  • For example, the over-use of patches may be tempting, but this does not always represent quality refinement. 
  • After refinement, the software can cycle through the previous stages as many times as necessary until deployment. 

Understanding the Role of the Project Manager

As with all team-based methodologies, much of the success of a project relies on proper management. Therefore, the project manager throughout iterative development is highly influential on the quality of the final product. 

Perform Quantitative Monitoring
  • A project manager needs to understand the successes and failures of each and every iteration. 
  • A project manager should, therefore, identify quantifiable indicators that can reflect progress, and closely monitor those throughout development while ensuring the stability of previous iterations. 
Keep the Project On-Budget and On-Time
  • Successful project management means having a thorough understanding of where the project exists at every stage and iteration in the context of budget and timeline. 
  • Neglecting this can result in consequences such as devastating "crunch" times and budget crises. 
Mitigate Risk
  • Even though proponents applaud iterative development for its comparatively low risk against other design methodologies, the project manager should still have a solid understanding of risk and risk mitigation.
  • This means carefully planning each iteration and stage to maximize efficacy and minimize losses of time and energy.

Differences Between Agile Development and Waterfall

  • One major difference between Agile development and the waterfall model is the variable of time. 
  • An iterative model enables time-boxed, piecewise, and evolutionary development with flexibility for backtracking. 
  • Alternatively, a waterfall model relies on gating and boxing by functionality, in which a high-risk-high-reward scenario of comprehensive, detailed development followed by coding, testing, and release entails less flexibility in development. 

  • Naturally, the larger the scale of the project, the higher the risk is for waterfalling. 
  • Iterative software development is a valuable mechanism for the production of high-quality products. 
  • Following decades of refinement, this methodology is especially effective for large projects thanks to its time-boxed nature and stratified processes. 

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