Driving to ZBB

With the successful release of Whidbey Beta1 a few weeks ago, we’re now moving toward Beta2. The next key milestone between now and Beta2 is “ZBB.” It is critical to close down on open issues during the drive to ZBB, because doing so significantly impacts our execution efficiency for months to come. Hitting this deliverable is one of the key things we must do right now to ensure success at Beta2.


So, what exactly is this impactful thing we call “ZBB”. ZBB is an acronym used internally for “Zero Bug Bounce”. In a single sentence, it is a point in the project where we have zero bugs for the milestone. The importance of reaching this milestone in a project is to not only reduce any backlog of bugs, but also to help ensure that we’re on track for delivering a quality release at the end of the milestone with the issues slated to be resolved, done.


A general schedule that includes ZBB would look some thing like:

1) Feature coding

2) Integration of bits between feature teams

3) Bug fixing period, open issue resolution

4) ZBB

5) “Bounce”* (zero bugs in the queue at this point)

*“Bounce” = expectation that additional bugs will be coming in.

6) Continue triage and fixing bugs that directly affect the milestone release.

7) Ship for the milestone (e.g. a Beta)


At step 3, we will hold reviews with each team and ask them to provide status on their features and bug counts. An important aspect of the bug count status is the trajectory of their current (bug) count to zero, and the math they’re using to get there. An aggregation of this data allows us to find problems early and manage them as necessary. It helps to give us better planning toward and confidence on Step 7. Additionally, asking the teams for the ‘math’ they’re using to determine their downward bug trajectory allows us insight into the validity of the projected dates. In other words, going thru the exercise and providing data on the math allows both the product team and the release team a better understanding and confidence of why the date is what it is. It also helps us to manage the factors that may be causing issues with the trajectory. For example, their math may indicate that they need more balanced resources.


All this to say; we’re currently in Step 3 for Whidbey Beta2 and are working with teams to understand their ZBB dates. From there we’ll be determining how to best reach ZBB and drive the division teams to make sure we hit ZBB on time…this will help to put us at high confidence for shipping Beta2!