I was lucky enough to do an internship in a company that embraces agile software development, and for a young developer, this allowed me to have an overview of something that will have an integral part in my professional career.

This blog post sums up what I have understood to be good practice in defining requirements for a project, thanks to the tips I have gathered from this experience and certain courses I have attended to.

Characteristics of quality requirement statements

In order to define good software requirements, one should always keep in mind 6 distinct characteristics.

A software requirement must be...

Correct

Every requirement must accurately describe the functionality to be delivered.

Feasible

The implementation of the functionality must be realistic and possible within the known capabilities and limitations of the system and its environment.

Necessary

A requirement should represent something the customer really needs.

Prioritized

Each requirement needs to have an implementation priority in order to facilitate reaction to new requirements being added, a team changing or when facing budget cuts.

Unambiguous

A requirement should deliver one interpretation, no matter the reader. Therefore subjective words should be avoided and succinct, simple language should be used.

Verifiable

A requirement must and will be tested by its developers, therefore it must be possible to devise test cases for it.

Characteristics of quality requirement specifications

Requirements statements are only a small part of a larger product / system, with that in mind, we must consider how individual requirement statements hold alongside other existing and new requirement statements. Which leads us to look into characteristics of quality requirement specifications.

A software requirements specification (SRS) is a "description of a software system to be developed. It lays out functional and non-functional requirements, and may include a set of use cases that describe user interactions that the software must provide" (Source: Wikipedia).

In order to have the best SRS possible, it should follow these characteristics.

A software requirements specification must be...

Complete

No necessary information or requirements should be missing in order to develop the product.

Consistent

It is vital that requirements do not conflict with other requirements.

Modifiable

One must be able to modify a requirement without impeding on other requirements. This brings up the necessity of grouping up requirements that are linked, and to create a cross-reference listing.

Traceable

Linking each requirement to its source is essential, to achieve it, each requirement must be written in a structured and precise way (as opposed to a narrative and large approach).

Final thoughts

Agile software development took its rightful place as it advocates continuous improvements, adaptive planning alongside many other principles. Utilizing it to its full and best potential can be a daunting task for any newcomer like myself, but I hope this short blog post covers my general understanding of defining quality requirements for a project to a good degree.

Thanks for reading !