One of the questions that seems to frequently come up in my discussions these days is:

What’s the difference between a Requirement and a Feature?

Let me try and explain this difference in this short blog post.

What is a Requirement?

One of my favorite books on requirements, “Software Requirements,” by Karl Wiegers defines a requirement as follows:

A statement of a customer need or objective, or of a condition or capability that a product must possess to satisfy such a need or objective.

Another of my favorite books on requirements, “Mastering the Requirements Process,” by Suzanne & James Robertson defines a requirement as follows:

A requirement is something the product must do or a quality it must have.

Great definitions, both. Taking these into account, I’d define it as follows:

A requirement is a capability that a product must possess or something a product must do in order to ultimately satisfy a customer need.

A requirement tends to be more granular, and is usually written with the implementation in mind. Those who consume requirements tend to be engineers or technical audience.

What is a Feature, Then?

Again, culling from the books linked above, I’d define a feature as follows:

A feature is a set of related requirements that allows the user to satisfy a business objective or need.

A feature tends to be a “higher-level” objective than a requirement - and is usually more focused on business needs rather than implementation.

Usually a feature is something you’ll print on a detailed datasheet of your product/service - i.e. intended to be shared with your customers and prospective customers.

An Example

Do you find the definitions above a little hazy? Here’s an example to help give you a more tangible feel. Let’s say you’re designing an online bookstore to compete with Amazon. [P.S. I wish you good luck, you’re gonna need it! ]

For such a project, here’s an example of a feature:

• 1-Click Ordering

Here are some examples of requirements related to this feature:

• User shall be able to activate 1-click ordering within his account
• User shall be able to deactivate 1-click ordering within his account
• User shall be able to order books with just 1 click
• …
• User shall be able to “Undo” his 1-click order for a period of 30 minutes from the time he placed such an order

I hope you find this brief blog post helpful to understand the distinction between a requirement and a feature.

Please chime in with your thoughts or perhaps an even better definition - click here to let your thoughts known…