Are you a project manager or are you aspiring to be one? Well, being involved in projects is always exciting, some people would say especially for software projects. In this blog, I’ll give you a brief overview of four software development lifecycles.

This is usually used for projects where the customers’ situation and goals are fairly static and not likely to change. When using the waterfall model you progress through the stages in a linear fashion with the first phase dedicated to requirements task. The first milestone occurs when a complete set of functional, performance and other requirements have been documented, validated and approved by the user. Making sure requirements are stable early in the project life cycle make project work much easier.

Each cycle or level in the spiral model includes different activities found in phases of the waterfall model. This model is used to reduce project risk incrementally in other words as you progress through the project the risks decrease, in more detail this is how it is accomplished. At the end of each cycle, stakeholders will analyse risks and develop appropriate mitigation plans to use at the next level. The documents and new requirements are then sent on to the next level and this happens again and again after each cycle.

The spiral model is used in situations where the requirements are not know up front, the model then allows the capabilities from the users to become clear plus something is delivered faster. In another case the requirements may not be completely know up-front, but the basic operational needs and concepts are known, so projects can begin and allow the future evolutions’ requirements to be determined over time. The first milestone usually occurs in the spiral under these conditions: requirements for the spiral are complete and agreed to by the user concurrently with an operational concept, plans, design and code.

The unified process divides the project into four phases. This first phase of the inception phase has typical goals like the following:

Establishing a justification or business case for the project
Establishing the project scope and boundary conditions
Outlining the use cases and key requirements
Identifying risk
Preparing an initial project schedule and cost estimate

The lifecycle objective milestone marks the end of the inception phase. To develop an approximate vision of the system, make the business case, define the scope, and produce rough estimate for cost and schedule.

Each cycle or level in the spiral model includes different activities found in phases of the waterfall model. This model is used to reduce project risk incrementally in other words as you progress through the project the risks decrease, in more detail this is how it is accomplished.

In the agile model no detailed documentation and design is required and the start-up. Which means you jump straight into development stage, however, flexible systems engineering support during the project is needed to make things run properly.

Typically, small efforts are performed and the set of requirements is focused on small, specific capabilities with the users and developers teaming to work the interplay of requirement and capabilities together. Agile is named agile because of the agility that needs to be found in your development. There should be very short cycles that allow user collaboration from start to finish, close team work, constant communication among participants, the ability to adapt to change and incremental development.

The goal of using the agile model is to develop working functional software that meets the users’ needs, not produce detailed requirements or documentation.

I have had the chance to take part in projects that have used these models, in my short project management life. Personally I think the model we use at Clapdigital is the best for modern development and design. What do you think?