Relative Team Expertise and Story Sizing
In Parkinson’s Law of Triviality and Story Sizing, I touched on the issue of relative expertise among team members during collaborative efforts to size story cards. I'd like to expand on that idea by considering several types of team compositions.
Team 1 is a tight knit band of four software developers represented in Figure 1.
Their preferred domain and depth of experience is represented by the color and area of their respective circles. While they each have their own area of expertise, there is a significant overlap in common knowledge. All four of them understand the underlying architecture, common coding practices, and fundamental coding principles. Furthermore, there is a robust amount of inter-domain expertise. When needed, the HTML5/CSS developer can probably help out with JavaScript issues, for example. The probability of this team successfully working together to size the stories in the product backlog is high.
Team 1 represents a near-ideal team composition for a typical software related project. However, the real world isn't so generous in it's allocation of near-ideal, let alone ideal, teams. A typical team for a software related project is more likely to resemble Team 2, as represented in Figure 2.
In Team 2, the JavaScript developer is fresh out of college, new to the company and new to the business. His real-world experience is limited so his circle of expertise is smaller relative to his teammates. The HTML5/CSS developer has been working for the company for 10 years and knows the business like the back of her hand. So she has a much wider view of how her work impacts the company and product development. As a team, there is much less overlap and options for helping each other through a sprint is diminished. As for collaborative story sizing efforts, the HTML5/CSS and C# developers are likely to dominate the conversation while the JavaScript developer agrees with just about anything not JavaScript related.
As Agile practices become more ubiquitous in the business world, team composition beings to resemble Team 3, as shown in Figure 3.
The mix now includes non-technical people - content developers and editors, strategists, and designers. Even assuming an equal level of experience in their respective domains, the company, and the business environment, there is very little overlap. Arriving at a consensus during a story sizing exercise now becomes a significant challenge. But again, the real world isn't even so kind as this. We are increasingly more likely to encounter teams that resemble Team 4 as shown in Figure 4.
As before, the relative circle of expertise among team members can vary quite a bit. When a team resembles the composition of Team 4, the software developers (HTML5/CSS and C#) will have trouble understanding what the Learning Strategist is asking for while the Learning Strategist may not understand why what he wants the software developers to deliver isn't possible.
When I've attempted to facilitate story sizing sessions with teams that resemble Team 4 they either become quite contentious (and therefore time consuming) or team members that don't have the expertise to understand a particular card simply accept the opinion of the stronger voices. Neither one of these situations is desirable.
To counteract these possibilities, I've found it much more effective to have the card assignee determine the card size (points and time estimate) and work to have the other team members ask questions about the work described on the card such that the assignee and the team better understand the context in which the card is positioned. The team members that lack domain expertise, it turns out, are in a good position to help craft good acceptance criteria.
Who will consume the work product that results from the card? (dependencies)
What cards need to be completed before a particular card can be worked on? (dependencies)
Is everything known about what a particular card needs before it can be completed? (dependencies, discovery, exploration)
At the end of a brief conversation where the entire team is working to evaluate the card for anything other than level of effort (time) and complexity (points), it is not uncommon for the assignee to reconsider their sizing, break the card into multiple cards, or determine the card shouldn't be included in the sprint backlog. In short, it ends up being a much more productive conversation if teammates aren't haggling over point distinctions or passively accepting what more experienced teammates are advocating. The benefit to the product owner is that they now have additional information that will undoubtedly influence the product backlog prioritization.