Articles for 'Karl Wiegers'

Scope creep (also known as feature creep, requirements creep, featuritis, and creeping featurism), however, refers to the uncontrolled growth of functionality that the team attempts to stuff into an already-full project box. It doesn’t all fit. The continuing churn and expansion of the requirements, coupled with inadequate prioritization, makes it difficult to deliver the most important functionality on schedule. This demand for ever-increasing functionality leads to delays, quality problems, and misdirected energy.  Scope creep is one of the most pervasive challenges of software development. 

 

The end products of requirements development for a business analytics project will be similar to those for any other project—a set of business, user, functional, and nonfunctional requirements. Process flows, use cases, and user stories can reveal that someone needs to generate analytics results, and performance requirements describe how quickly they need results, but none of these uncovers the complex knowledge required to implement the system... An effective elicitation strategy for business analysts (BAs) is to drive requirements specification based on the decisions that stakeholders need to make to achieve their business objectives.

Most discussions about software requirements deal with business information systems and similar projects. The world is also full of products that use software to control hardware devices, broadly called embedded systems. Among countless examples are cell phones, television remote controls, kiosks of all sorts, Internet routers, and robot cars.  This is the first article of two that will discuss some of the requirements issues that are especially important to embedded and other real-time systems.

The context diagram and the use case diagram are two useful techniques for representing scope. This article describes two other methods for documenting scope: feature levels and system events.

With the rise in popularity of agile methods, business analysts and product owners often use the term “agile requirements” to label their work.  We do not care for the term “agile requirements” because it implies that the requirements for an agile project are somehow qualitatively different from those for projects following other life cycles. A developer needs to know the same information to be able to correctly implement the right functionality regardless of the life cycle being used.

So you’ve developed a set of requirements for some portion of your next systems development project. Now what? Experienced project managers and software developers understand the value of translating requirements into rational project plans and robust designs. These steps are necessary whether the next release represents 1 percent or 100 percent of the final product. As shown in Figure 1, requirements serve as the foundation for project plans, designs, code, and tests. In addition to these connections, there is a link between the requirements for the software to be built and other project and transition requirements. Those include data migrations, training design and delivery, business process and organizational changes, infrastructure modifications, and others.

Every software team talks about project scope and team members often complain about unending scope creep. Unfortunately, the software industry lacks uniform definitions of these terms, and the requirements literature is short on clear guidance regarding how to even represent scope. I confront scope head-on in this series of three articles...

 Managers often ask me what return on investment (ROI) they can expect from the money they spend on training, process improvement, and tools for requirements engineering. I’d love to give them a nice, tidy answer—but I can’t. As with so many questions in software, the correct answer is, “It depends.” This article explores some of the factors that influence what ROI an organization can expect from better requirements.

People sometimes say that requirements are about “what” and design is about “how.” There are two problems with this simplistic demarcation.  This makes it sound as though there’s a sharp boundary between requirements and design. There’s not. In reality, the distinction between requirements and design is a fuzzy gray area, not a crisp black line. I prefer to say that requirements should emphasize “what” and design should emphasize “how.” 

Rather than expecting use cases to contain all of a system’s functionality, I prefer to employ use cases to help the business analyst discover the functional requirements. That is, the use cases become a tool to reveal functionality rather than being an end requirements deliverable themselves. Users can review the use cases to validate whether a system that implemented the use cases would meet their needs. The BA can study each use case and derive the functional requirements the developer must implement to realize the use case in software. I like to store those functional requirements in a software requirements specification, although you could add them to the use case description if you prefer.

It is certainly true that use cases are a powerful technique for discovering the functional requirements for a system being developed. However, this statement suggests that use cases are the only tool needed for representing a software system’s functionality. In most cases, they aren't.

The structure that use cases provide is far superior to the nearly worthless technique of asking users “What do you want?” or “What are your requirements?” In this article I share my perspectives on when use cases work well, when they don’t, and what to do when use cases aren't a sufficient solution to the requirements problem.

Software developers often want to freeze the requirements following some initial requirements work and then proceed with development, unencumbered with those pesky changes. This is the classic waterfall paradigm. It doesn't work well in most situations. It’s far more realistic to define a requirements baseline and then manage changes to that baseline. This article defines the requirements baseline and describes when to create one.

An alternative to eliciting use cases and user stories is to identify the external events to which the system must respond. An event is some change or activity that takes place in the user’s environment that stimulates a response from the software system. An event-response table (also called an event table or an event list) itemizes all such events and the behavior the system is expected to exhibit in reaction to each event.

Tracking project status means comparing where you really are at a particular time against the expectation of what “complete” means for this development cycle.  Monitor the status of just those functional requirements that were committed for the current release, because that’s the set that’s supposed to be 100 percent done before you declare success and ship the release.