Comparing Agile and Lean Backlog Strategies

 

One of the changes that we made in the DA 5.3 release on September 30th was to update our advice around managing backlogs. We had been using older terminology from when we first developed Disciplined Agile Delivery (DAD) and we had an out-of-date description of what was being advised in the Scrum community (they've adopted a more disciplined strategy in recent years).  So we've acted and updated this aspect of the tool kit.

Recent Refactorings

There are three refactorings that are pertinent to our discussion:

1. Introduction of the Intake Work process goal. In the DA 5.2 release of July 9th, 2021 we created a new process goal, Intake Work by refactoring it out of the existing Address Changing Stakeholder Needs process goal.  The Intake Work process goal is depicted in Figure 1. The reasons for this refactoring was that Address Changing Stakeholder Needs wasn't cohesive in that it had two purposes, the first to explore the changing needs and the second to intake the work into the team.   
2. Introduction of the Manage Backlog decision point. For the 5.3 release we refactored further, and split the Manage Work Items decision point into two, creating the new Manage Backlog decision point.  The reason for this refactoring was that the original decision point wasn't cohesive, it had two purposes, the first to capture strategies to manage backlogs and the second to manage/visualize work items.
3. Update to Explore Scope. We updated Explore Scope's Choose a Backlog Management Strategy decision point to reflect the changes we made to Intake Work.

Figure 1. The Intake Work process goal.

Managing Backlogs

As you can see in Figure 1 there are four fundamental strategies for managing your backlog of work.  These strategies are ordered, you know this because there is an arrow beside the list, indicating that the strategies towards the top of the list are generally more effective than the strategies towards the bottom.  In order from most effective to least effective, these strategies are:

1. Lean backlog. Lean backlogs are typically organized into four groupings: Potential work that the team may commit to; Committed work that the team will perform, which is typically sequenced into several classes of service; Work in process (WIP) that the team is currently performing; and completed work that is ready to move on to the next stage in your overall process.  Lean backlogs are overviewed in Figure 2. 
2. Agile backlog. Work items are managed as an ordered list/stack. Higher-priority work items appear at the top of the list, are granular and captured in greater detail, and are sequenced.  Lower-priority work appear towards the bottom of the list, lack detail, and are effectively in unsequenced priority buckets. In previous versions of DA we referred to this strategy as a Work Item List and it has always been our default recommendation for agile team.  This strategy was an extension to Scrum's (at the time) product backlog which was a prioritized list of requirements, but over the years Scrum's approach has evolved into this more disciplined strategy. Agile backlogs are overviewed in Figure 3.
3. Requirements (product) backlog.  A unique, ranked stack of requirements that needs to be addressed. Requirements at the top of the list should be captured in greater detail than lower-priority requirements at the bottom of the list. In earlier versions of Scrum this was a prioritized list of functional/usage requirements, often captured as user stories.  Some teams would include defects and some form of quality requirements (often captured as technical stories) on the backlog, as they were considered valid requirement types as well. Requirements backlogs are overviewed in Figure 4.
4. Unsequenced backlog. All of the work is effectively the same priority, although sometimes there may be the concept of two priorities - what is in the current release and what needs to be in future releases.

Figure 2. Lean backlog overview.

Figure 3. Agile backlog overview.

Figure 4. Requirements (product) backlog overview.

Comparing Backlog Strategies

The following table compares the four backlog strategies.  For more information, please refer PMI's Disciplined Agile (DA) Browser.

Acknowledgements

I'd like to thank Curtis Hibbs and Klaus Boedker for their great work on Figures 2-4, which I reused from our upcoming Disciplined Agile Product Owner workshop.