Software Development Approaches

The Software Development Process is the structured approach to developing software for a system or project, sometimes called the Software Development Life Cycle (SDLC). Several approaches can be used, including waterfall, spiral, Agile, and incremental development. These different approaches will focus the testing effort at different points in the development process. However, each approach is composed of the same basic steps of development. The incremental development approach typically forms the basis for software development within the larger systems level of Evolutionary Acquisition (EA). [1,2]

Definition: A software development process is a way to improve design and product management by breaking software development work into smaller steps or sub-processes that can be done in parallel or in-order.

Types of Software Development Approaches

The Software Development Approaches below show how the various tasks related to software development can be organized. Typical approaches or paradigms encountered in DoD software development include waterfall, incremental, and spiral as described below. The incremental development approach typically forms the basis for software development within the larger systems-level of Evolutionary Acquisition (EA). There are fur main types of software development approaches which are:

Waterfall Approach
Incremental Approach
Spiral Approach
Agile (Scrum)

Waterfall Approach

Development activities are performed in order, with possibly minor overlap, but with little or no iteration between activities. User needs are determined, requirements are defined, and the full system is designed, built, and tested for ultimate delivery at one point in time. A document-driven approach best suited for highly precedence systems with stable requirements.

The waterfall model is often also referred to as the linear and sequential model, for the flow of activities in this model are rather linear and sequential as the name suggests. In this model, the software development activities move to the next phase only after the activities in the current phase are over. However, as is the case with a waterfall, one cannot return to the previous stage.

Incremental Approach

Determines user needs and defines the overall architecture, but then delivers the system in a series of increments
(“software builds”). The first build incorporates a part of the total planned capabilities, the next build adds more capabilities, and so on, until the entire system is complete.

Spiral Approach

A risk-driven controlled prototyping approach that develops prototypes early in the development process to specifically address risk areas followed by an assessment of prototyping results and further determination of risk areas to prototype. Areas that are prototyped frequently include user requirements and algorithm performance. Prototyping continues until high-risk areas are resolved and mitigated to an acceptable level.

During each iteration or loop, the system is explored at greater depth and more detail is added. Appropriate for exploratory projects that are working in an unfamiliar domain or with unproven technical approaches. The iterative nature allows for knowledge gained during early passes to inform subsequent passes. Requires low up-front commitment.

Agile and Scrum Approach

The Agile software development process and its most popular method, Scrum, use a dynamic and iterative way to build software. In contrast to the strict, sequential flow of the Waterfall process, cross-functional teams in Agile work in “Sprints” of a week or a few months to build and release software that customers can use and give feedback on. Agile is all about moving quickly, putting out new versions often, and responding to what your users really need, even if that goes against what you had planned. This means you don’t need a full list of requirements and a full SOW before starting work. Instead, you move in one direction with the idea that you will change directions along the way.

Software Development Process Metrics

Software metrics should be an integral part of the software development processes. Program Management Offices (PMO) should gain insight into proposed metrics during source selection, and developers should commit to the consistent use of those metrics, including collecting, analyzing, and reporting. Metrics chosen for use should be defined in the Software Development Plan (SDP). Software metrics should: [1]

Be integral to the developer‘s processes.
Clearly portray variances between planned and actual performance.
Provide early detection or prediction of situations that require management attention.
Support the assessment of the impact of proposed changes on the program.

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Updated: 11/25/2022

Rank: G5.5

Software Management