I’ve mentioned elsewhere that my team struggles to find the right balance for design reviews (see Working Agreements for Agile Teams (Part 4)). My initial challenge was to get people to recognize the need for collaborative design. Then to get collaboration to occur and finally raise the bar on the quality of the collaboration so we improved our designs.
Its taken 18 months to learn to collaborate effectively on design. I’m confident of this because our last team meeting involved a discussion on the team’s expectations on the amount of collaboration needed for different design activities. You can’t have that discussion if people aren’t trying.
I wanted to share some details of that discussion because the intent and scope is valuable to others.
The team discussed two examples. In both cases, the design activity was handled by another team. The required software changes involved parameter changes. Parameter changes in our application typically involve changing values in a configuration file or the source code. Simple changes to make in the source code but with far reaching implications.
The question asked during the team meeting was how much involvement did the team want with the other team in order to fulfill the working agreement. Our working agreement requires the author and two others engage and agree on the scope of the design. Basically, accept the parameter change as a trivial software change or consider the broader implications.
The source code change isn’t the important factor affecting the design activity. Other factors include knowledge of why these parameters need to change and the rationale for choices made regarding their manipulation by the application. This information is needed to make future changes. It also involves understanding the requirement that the other team was trying to fulfill.
The team discussion focused on the degree of engagement required by other team members when knowledge and experience is important. Having this conversation is a huge win as it level-sets expectations and ensures that rich and meaningful engagements occur between team members.
This is what a working agreement should foster: an environment where expectations can be set and met and discussion where team members can level-set on expectations with each other.
This level-set is an important component of developing team norms.
I’ve reached the point where I have enough data to calculate a meaningful velocity for my team. I defined velocity as the median of the story points completed in each sprint during the last six months.
I use the median because its a more robust statistic than an average. By robust, I mean it changes more slowly and is less susceptible to outliers.
I am concerned how this model will work for us, particularly when it involves schedule projections. I collect six months of data to permit a four month projection. (Using six months of data is an arbitrary decision.)
I present the velocity during the sprint planning meeting as guidance. As guidance, I acknowledge that velocity is a model of team capacity. The team may have reasons to plan for more or less work.
I didn’t count on people’s reactions to this model. They challenged it
using individual and team absences.
A median accounts for things like statutory holidays, vacations, and student turn-over. Absences make the median lower than it would be if everyone were present.
The model doesn’t address extremes. A holiday shutdown (and the resulting velocity) can be excluded.
using the accuracy of the story point estimates.
Using powers of 2 to estimate story points and a median makes the calculation conservative, not aggressive. Mitigations for poor story point estimates include swarming and point changes until story is added to a sprint.
pointing out that adding people didn’t change the velocity.
A median taken over 13 sprints with team of 8 doesn’t move much when someone is added or removed from the team. These changes won’t affect velocity for at least 6 sprints.
This is a benefit when dealing with students who change every four months. It is a disadvantage when you add or remove a full time person and management can’t see the impact immediately.
People didn’t buy the argument that the model accounts for absences. If you have a statutory holiday once a month and run two sprints each month, then the velocity of both sprints includes the reduced capacity introduced by the holiday.
I agree vacations during the holiday season introduce more pressure on velocity. In my environment, people tend to take more vacation during the summer and in December. Fewer people means less capacity and smaller velocity. If fewer people results in more velocity then other challenges exist.
The absence argument is hard to explain since velocity is presented as guidance. This argument implies people didn’t percieve velocity as guidance or felt that they weren’t empowered to use this information.
Poor estimates are challenging. In our case, the team provides estimates and can change them at any point up to commitment into the sprint. I say this, because adding a story to a sprint is a commitment to deliver it.
The method used to generate story point estimates and velocity is conservative and should buy the team additional buffer for poor estimates. When using powers of two for story points, any debate on the story points that can’t be resolved should drive the story point estiment to the next higer powe of 2. This implies that every situation like this introduces up to 100% buffer into estimate.
We agree to document our design and review the design with at least two people prior to implementation.This agreement positions the team to avoid situations where only one person understands the design. It's simplistic. If you dwell on it you may conclude it's heavy handed. Taken literally, this working agreement requires every design review to involve three people.