What are the main differences between waterfall and iterative development methodologies?

Remember to compare the phases, budgeting techniques, change management procedures, and team structures for these two models. Also, be sure to mention the business scenarios in which these two styles add value.

"At the highest level, the main difference between waterfall and iterative development is that the phases of waterfall projects happen in succession and iterative methodologies deliver products incrementally.

Waterfall projects typically have a set budget and timeline, and each phase is tightly managed. Members of the project team play a more or less critical role depending on the phase of the project. For example, an analyst would drive the analysis phase and engineers drive development. Resources provide estimates for the entire project of work before detailed analysis is complete and project managers use change management procedures to negotiate scope change requests throughout the project.

The product or products that are developed in waterfall projects are tested and accepted by their users at the very end of the project. This approach causes conflict and sometimes even failure because there can be a disconnect between what customers had in mind and what is actually built. Additionally, waterfall projects are often lengthy, and the needs of the customer sometimes change before the project can be implemented.

Waterfall has its cons, but it can be a great fit in certain scenarios. Waterfall is typically preferred in situations that have tight regulations over the various phases involved. Trying to deliver these types of products iteratively often causes confusion and extraneous overhead that is avoided by approaching the work traditionally.

In contrast, iterative projects deliver valuable and working products on an incremental and continual basis. Teams partner closely with their customers throughout the entire process to define a high-level vision, prioritize the available work, and refine it as the product is developed. There are several methods for establishing budgets and estimating work in these models, but in general, teams give rough estimates and refine them as they get closer to a specific body of work.

One of the major pros of this model is that working assets are delivered sooner and have a chance to be used and reviewed early in the process to allow customer feedback to enhance future development. Also, this style of development is valued in business scenarios where customers expect continual delivery of new features.

Waterfall and iterative teams usually lean on similar skill sets, but the roles are sometimes different. For example, an agile scrum team may not have a project manager and may elect to spread project management duties across the product owner and scrum master roles."