In this final of this six-part blog series, Shirley provides practical advice on adopting Agile Development methodologies.
Agile Development is a software development methodology based on incremental, iterative development, where requirements and implementations evolve through collaborative, self-organizing, cross-functional teams. Agile Development promotes product delivery as a time-boxed series of functional and potentially shippable product increments that enables teams to rapidly respond and adapt to change.
Part VI – Scaling
Velocity is the sum of the story points a team completes in a single Sprint. Velocity for any given team will depend on the team composition and the calibration used for relative sizing.
Measuring and understanding a team’s velocity is important for several reasons:
- During sprint planning, use the team’s velocity to corroborate the cumulative story points being committed. Note: Target velocity for any given sprint should be adjusted to reflect time that delivery team members will be absent (e.g. vacation, holidays).
- As the team grows and/or invests in knowledge transfer, you can measure and take advantage of changes in velocity.
Story Size and Sprint Commitments
Once you are measuring velocity, a good rule of thumb for successful sprint planning is not to commit to any story greater than 50% of the total velocity of the team (i.e. if the average velocity of the team is 75, no individual story should be 40 points or greater.) Taking on larger stories will impose unnecessary risk on the team’s ability to complete the sprint, since they could ‘blow up’ with unexpected additional work and extend beyond the boundary of the sprint. If your backlog contains stories that are larger than the acceptable size for your sprint velocity, engage the Product Owner and Delivery team. Either break the story down into smaller stories with greater sizing accuracy, or refine the sizing with additional clarification from the Product Owner or by technical discovery (see ‘NMI Stories’ in an upcoming post on ‘Extending the Agile process’)
While measuring your team’s velocity using the original story sizes is a major step forward, you can increase the quality of your velocity measurement – and improve the team’s ability to size – by resizing stories when they are complete. Resizing should occur as close to the completion of a story (definition of done) as possible. Since resizing requires the involvement of everyone who worked on the story (developers, QA, etc.) I recommend resizing any stories that are newly ‘done’ immediately after the daily standup. This is best done at the scrum board where the story team can see all the resulting tasks and should take no more than 1-2 minutes. Ask the story team to collectively review how the story implementation had proceeded and listen for things like “the API turned out to be harder to stabilize than I’d expected. I had to build a lot more sample code” or “the implementation was so much easier than I expected (developer). It was much more challenging to test (QA)”. Essentially, let the team reflect on their implementation experience then pose the question. Do you still feel this is an 8? (that is, less than 1/2 the size of this 20?) Let the team come up with their resized number and write it on the story card next to the initial sizing.
Having this data will not only allow you to better measure the team’s velocity from sprint to sprint, but will also provide you a way to gauge how teams are sizing overall (are some teams more effective/accurate at than others?) and work more closely with the teams who need additional help.
Burn Down Charts
Burn down charts are used to track the progress or health of a sprint. Days in the sprint are plotted on the X-axis and total points are plotted on the Y axis.
Assuming a sprint or iteration progresses exactly to plan, the burndown would occur in a linear fashion, ending in 0 on the last day of the sprint.
Rarely do actuals track to the ideal scenario and, instead, points are added to the sprint, work takes longer than estimated, etc. While some Agile teams map their progress across all stories daily – by estimating how many points they have completed for open stories – I prefer to only burn down time when a story is complete – to avoid the risk of teams overstating the work completed. Plot your burndown using a single line for the ideal burndown and (most likely) a staggered line showing #points remaining that changes as stories are burned down completely.
If your burndown chart shows the team getting well ahead of ‘ideal’; burning down story points faster than planned, consider adding stories to the sprint. More likely, if your team is running behind the ‘ideal’ (on an overall basis – not any specific story) use this as an early indicator that you may have to drop or reduce scope of incomplete stories in order to deliver a potentially shippable (coherent) product increment.
Don’t be surprised if your ‘actual’ burndown goes up, not down from day to day. This could be a case of a story being resized (more accurately) after sprint planning, or more likely that work has been added to the sprint. When this happens, it’s another indicator of risk. Use the data to help you and the team decide if they are on a successful trajectory. Renegotiate commitments, trade for smaller stories with the Product Owner or trim individual story scope to bring the team back on track.
Like many things in Agile, burndown charts are not an absolute indicator of success or failure. It’s your job to manage the overall delivery risk and the burndown chart is a useful tool in that effort. Burndown charts showing ever increasing points remaining, or a lack of any stories fully burned down is a key indicator that something is off-track. Get together with your team and review what’s contributing to the dynamics you are observing (it could be that 3 stories are about to be completed), if the risk is real and what can be done to steer the team to success.
I’m sure as you’ve read these posts that it’s become clear that I believe that Engineering leadership has two responsibilities:
- Risk management/mitigation
- Team success and recognition
Agile provides the framework and the insights necessary to identify issues early and to work with the team to achieve a successful outcome. Agile empowers the team, through relative sizing, self-organizing, sprint commitments and collaboration to control their destiny in complex and rapidly changing situations. And, it provides the ability to demonstrate progress to the rest of the organization and establish a regular delivery cadence.
Together, Agile provides the tools and techniques necessary for even the most complex software project to be managed successfully. Successful teams and also highly motivated teams. Celebrate every little win as you adopt Agile – from a task being moved across the board, to a story being completed, to the Sprint Review demo. Take the time to reflect on how rapidly the product is evolving and how far you’ve come as a team (remind them how things used to feel when deliverables were late, QA was overwhelmed, etc.) and recognize everyone’s efforts.
Lastly, enjoy seeing your Agile proteges evolve. Before you know it, they will be guiding others in how to adopt the agile principles and it will be hard to remember life before Agile.