Quality requirements, also known as non-functional requirements (NFRs), quality of service (QoS) or technical requirements, address issues such as reliability, availability, security, privacy, and many other quality issues. The following diagram, which overviews architectural views and concerns, provides a great source of quality requirement types (the list of concerns). Good sources for quality requirements include your enterprise architects and operations staff, although any stakeholder is a potential source for them.
Figure 1. Architectural views and concerns.
Why Are Quality Requirements Important?
Stakeholders will describe quality requirements at any time, but it’s particularly important to focus on them during your initial scoping efforts during Inception as you can see in the goal diagram below for Explore Initial Scope. Considering quality requirements early in the lifecycle is important because:
Capturing Quality Requirements
Figure 2 depicts the goal diagram for Explore Scope. As you can see, there are several strategies for exploring and potentially capturing quality requirements.
Figure 2. The goal diagram for Explore Scope (click to enlarge).
Let’s explore the three strategies, which can be combined, for capturing quality requirements:
Of course a fourth option would be to not capture quality requirements at all. In theory this would work in very simple situations but it clearly runs a significant risk of the team building a solution that doesn’t meet the operational needs of the stakeholders. This is often a symptom of a teams only working with a small subset of their stakeholder types (e.g. only working with end users but not operations staff, senior managers, and so on).
In the following table we list the advantages, disadvantages, and considerations (when does the strategy makes sense) to compare whether a software architect should write code or not. You may recognize this approach from our book Disciplined Agile Delivery.
In the Disciplined Agile (DA) toolkit we’ve made it very clear that we expect Architecture Owners to be actively involved with the development of the solution. On Disciplined Agile teams the Architecture Owner is effectively a team member with additional responsibilities around leading the team through architecture decisions, in coaching them on architecture skills, and in working closely with your Enterprise Architecture team (if any) to ensure their development team understands and is working towards your organization’s technical roadmap.
We’re often told that it isn’t realistic to expect architects to write code. Invariably this is coming from people who are currently working in traditional IT organizations that have very well-defined roles, IT organizations that more often than not are struggling to be effective. Our response is always the same – Really? Are development teams following your architectural strategy? Are they eager to work with you, or are they forced to work with you? This generally leads to a discussion that reveals that things aren’t going so well for these architects in practice, and sometimes leads to a positive discussion as to how we can move towards a more effective approach for them. They kind of approach described in the Disciplined Agile (DA) toolkit.
Enterprise architecture, when performed in a disciplined agile manner, is an important enabler of agile software delivery. This is true for several reasons:
The Disciplined Agile Delivery (DAD) 1.x framework purposefully included the philosophy of enterprise awareness, the need for agile delivery teams to look beyond their immediate needs and consider the long-term needs of their organization. A common example of this is to work closely with your organization’s enterprise architects. The Disciplined Agile 2.0 framework, which we are incrementally publishing here at DisciplinedAgileDelivery.com, explicitly addresses Enterprise Architecture so that organizations may see how it fits into the overall strategy to build an agile organization.
When a disciplined agile project or product team starts, one of the process goals which they will likely need to address is Identify Initial Technical Strategy. This is sometimes referred to as initial architecture envisioning or simply initial architecture modeling. This is an important process goal for several reasons. First, the team should think through, at least at a high level, their architecture so as to identify a viable strategy for moving forward into construction. A little bit of up-front thinking can increase your effectiveness as a team by getting you going in a good direction early in the lifecycle. Second, the team should strive to identify the existing organizational assets, such as web services, frameworks, or legacy data sources, that they can potentially leverage while producing the new solution desired by their stakeholders. By doing this you increase the chance of reuse, thereby avoiding adding technical debt into your organizational ecosystem, and more importantly you reduce the time and cost of delivering a new solution as the result of reuse. You will do this by working with your organization’s enterprise architects, if you have any. This is an aspect of Disciplined Agile’s philosophy of working in an enterprise aware manner.
The process goal diagram for Identify Initial Architecture Strategy is shown below. The rounded rectangle indicates the goal, the squared rectangles indicate issues or process factors that you may need to consider, and the lists in the right hand column represent potential strategies or practices that you may choose to adopt to address those issues. The lists with an arrow to the left are ordered, indicating that in general the options at the top of the list are more preferable from an agile point of view than the options towards the bottom. The highlighted options (bolded and italicized) indicate default starting points for teams looking for a good place to start but who don’t want to invest a lot of time in process tailoring right now. Each of these practices/strategies has advantages and disadvantages, and none are perfect in all situations, which is why it is important to understand the options you have available to you.
Let’s consider each process factor:
We want to share two important observations about this goal. First, this goal, along with Explore Initial Scope, Coordinate Activities, and Move Closer to a Deployable Release seem to take the brunt of your process tailoring efforts when working at scale. It really does seem to be one of those Pareto situations where 20% addresses 80% of the work, more on this in a future blog posting. As you saw in the discussion of the process issues, the process tailoring decisions that you make regarding this goal will vary greatly based on the various scaling factors. Second, as with all process goal diagrams, the one above doesn’t provide an exhaustive list of options although it does provide a pretty good start.
We’re firm believers that a team should tailor their strategy, including their team structure, their work environment, and their process, to reflect the situation that they find themselves in. When it comes to process tailoring, process goal diagrams not only help teams to identify the issues they need to consider they also summarize potential options available to them. Agile teams with a minimal bit of process guidance such as this are in a much better situation to tailor their approach than teams that are trying to figure it out on their own. The DA process decision framework provides this guidance.
I was recently asked how is technical debt addressed in Disciplined Agile Delivery (DAD), a very important question. Because DAD promotes a full, explicit delivery lifecycle there are many opportunities to first avoid creating new technical debt in the first place and second to address existing technical debt appropriately.
Here are some of the strategies that DAD promotes when it pertains to technical debt:
There are many good online resources regarding technical debt, and the best single one that we have found is Israel Gat’s blog. Technical debt is real and you need a viable strategy to manage it. Otherwise you run the risk of slowly choking the life out of your organization’s IT infrastructure. The DA toolkit can help you to understand how the strategies described above fit into your overall agile delivery process.